First of all, I'm just going to say that item builds are often a matter of opinion, personal play-style and situational decisions. As such, effectively adapting your itemization largely depends on how you like the play.
Udyr
Taking a quick look through your match history, you seem to be favouring the Runic Echoes -> Iceborn Gauntlet build. Now, I'm not going to say that the build isn't good since that is obviously not true; if it wasn't good, it wouldn't be both the most used and highest win-rate build.
However, you have to consider what the build is optimally used for. That build excels at chasing, escaping and waveclear; it's a good build if you know how and when to pressure the map and apply pressure. This build is less useful for actually fighting enemy champions and it doesn't scale as well as other builds.
It might be a good idea to try the following to see how it suits you. My "typical" build tends to look something like:
or 
or 
, 
or 
, 
, 
, 
, 
Runes: Scaling CDR Quints and Glyphs, Scaling Health Seals, Attack Speed Marks
Masteries: 6/6/18 [Strength of the Ages]
Try to afford (at minimum) Boots of Speed, Hunter's Potion (after starting Refillable Potion) and Hunter's Machete (after starting Hunter's Talisman) on your first back.
While this build may look a little off, I find that it works quite well for me. I'm quite bulky between Seals, Strength of the Ages, Turtle Stance and levels, it makes me a powerful duelist and it provides a significant amount of mobility.
This build makes you a very powerful split-pusher who will quickly kill towers, can duel almost anyone they could send against you, and makes you very difficult to catch. The only draw-back is that it's rather expensive, which is why you have to farm a significant amount on Udyr (for both gold and a level advantage).
While I will cover it a little more in the "Jungle Tips" section later, I'll mention it now. Farming on junglers like Udyr is extremely important and you will want to take lane gold/experience whenever possible (without inconveniencing your team).
- If you get a kill, help them push the minions under tower.
- If your laner is backing after a gank, proxy the next minion wave.
- If your ally has left lane (died, backed, roaming), hold the wave for them and try to freeze it outside of their tower when you leave.
- Splitpush through the mid-game, farming up and creating pressure.
During a normal game, Udyr should be higher leveled than pretty much anyone else in the game and his farm should become comparable to a solo-laner as the game progresses.
Jungle Tips
I would suggest watching videos by high-ELO and/or professional junglers (i.e. Nightblue3, Stonewall008, TheOddOne, and foxdropLOL). They will typically provide a lot of useful tips while playing and you can often see or hear their decision process and some optimizations throughout the game.
Off the top of my head, some basic optimizations may be:
- Use hard-CC when the monster camps are about to attack you to cancel that attack and delay their next.
- Each of the smite buffs are quite useful in different situations. Be sure to take proper advantage of them.
- Raptor's buff is great for ganking
- Gromp buff provides extra damage during clears and fights, especially for champions with a lot of health
- Krug's buff reduces the damage you take while clearing and lets champions without CC kill Scuttle Crab faster
- Wolf buff is useful when you are being counter-jungled or invaded (or after your initial towers have fallen).
- If you have a weak early clear, Krugs -> Raptor's -> Red Buff is probably the route that conserves the most health.
- Kill the little Raptors and the little Krug first on single-target clearers. They deal a significant amount of damage for their health value, so you will be healthier if they die early.
- If you think the enemy jungler will invade you early game, it can be safer to start on a buff camp rather than a little camp since you are less likely to be where they are looking.
- Attack Speed is extremely efficient at clearing on most junglers. I'd recommend using about 15% on champions when you need to speed up their clear even if they don't use the stat much later (with a few exceptions, such as Nidalee and Evelynn).
- Keep a pink ward out (or in your inventory) whenever possible. This is important for every champion, but I thought I should emphasis it. There isn't really a good reason not to.
As far as ganking is concerned:
- When possible, conserve your gap-closer while ganking. If you can get to the enemy champion without using your mobility spell(s), then you can save it to catch them after they try to escape (Flash, dash, blink, etc).
- Melee champions should try to stay between the enemy and their escape route. You should be trying to move backwards (towards their escape) in-between attacks so that you can body-block them and slow their escape. This also leaves you closer to them if they try to dash on blink past you.
- Use Raptor's smite buff to determine if you have been spotted by wards when ganking to reduce the risk of them escaping or receiving a counter-gank.
- It can be risky to gank top-lane while Dragon is up since the enemy team can just group and take it 4v3. I'd recommend ganking top-lane early if possible (after your initial clear) and when Dragon is down; that lane can be quick snowbally due to isolation, so you want to get your ally ahead.
- Learn to recognize the general times when buff camps spawn during games. If you see the enemy gank bottom lane while their top-side buff is up, you can go steal it from them.
- Watch when top and bottom lane initially go into lane. If that lane has leashed for their jungler (missing health, mana, or showed up to lane a bit late), then you know where the enemy jungler has likely started and where they will end their clear (where is closest for them to gank).
- If you have killed the enemy laner, you can either allow your laner to freeze or shove the lane into the enemy tower. If you shove the wave under tower and the next minion wave is coming up, it can be helpful to proxy it to ensure that the wave fully resets and the enemy laner misses as much as possible. This is very situational though and you will have to learn when through experience.
Other tips:
- Whenever possible, walk up to the enemy champion during a gank and save your gap-closer for after they use their escape abilities.
- Watch the enemy laners when they go into lane. Whichever lane shows up later and/or missing mana will likely indicate which side of the jungle the enemy jungler started on (which is useful for predicting gank paths and for counter-jungling).
- When against aggressive early counter-junglers (i.e. Shaco) it can be a good idea to start on your buff camp and/or to start on a different side than you usually do. If he invades your buff, you've already taken it and/or you aren't there to be killed.
- Watch the minimap to see when and where the enemy goes to ward, which laners are pushing, which laners are vulnerable
- Know, roughly, how most laning matchups go so that you can prioritize which lanes are the easiest to gank or require an early gank to decide the matchup.
- If you have blown an enemies Flash during a gank but haven't killed them, swing back around immediately after an gank them again. Many people don't expect it
- If you've killed an enemy during a previous gank in top lane, kill them again immediately after they return to lane. They likely won't have wards up yet and a second back-to-back death can be enough to completely crush any chance that opponent has to recover the lane.
- Top laners rarely bother warding the lane bushes. As such, lane ganks can be quite surprising and effective.
- When you kill an enemy laner, shove the minion wave into the tower so they miss gold and experience and so that the minion wave will reset to the middle of the lane. If you can get away with it, clear the upcoming minion wave as well to ensure the reset and maximum missed minions.
You will learn a lot through experience, but these tips should help you at the start.
Singed
I have less experience with Singed (and not much recent), but I'm curious as to whether you would benefit from more mana sustain for long fights and trading. Looking at your build, Corrupting Potion seems to be your only source of mana for most (or all) of the game. While you don't want to stack mana on Singed, I wouldn't recommend going entirely without it either.
For mana sustain, I would recommend one of the three following options:
- Doran's Ring will be useful when you are clearing minion waves and trading since it increases your damage in addition to providing mana and health.
- Sapphire Crystal is a cheap option, but it should provide enough mana (and a little health) to hold you over for the rest of the game. You can sell it later or build it into something if you wish.
Tear of the Goddess provides a significant amount of mana (and health) as the game progresses. When fully stacked, it should be near gold efficient entirely from the health it provides through Singed's passive and you shouldn't worry about running out of mana at any point. You can choose to build it into Seraph's Embrace late-game (damage, shield) or sell it for something else (since your base mana pool should be sufficient at this point).
While this may not be the optimal set-up, it's a minor delay for your Rylai's Crystal Scepter in exchange for better mana sustain.
Aside from that (which is largely my personal opinion), your builds don't really seem to have any issues. Sunfire Cape and Abyssal Scepter are a little questionable (since you will often not be in range for them to take effect), but I can see your reasoning.
to 
. 2 Reasons .. first, they don't expire (also cleaned faster), second the huge increased range