I don't play very much ranked, however I do have a lot of general game knowledge and, despite the fact that I'm lower rank than you, can probably give you some tips.
For jungle: ask lanes to call out when someone's flash is down, and turn on timestamps in chat so you know about when their flash is coming back up. Take a look at the enemy's flash in the screen to see if it's on a 300 or 270 second cooldown. Then, until either 5 minutes after they flash or 4 1/2 minutes after they flash, depending on if they have Insight or not, gank that lane a lot. One mistake I often make when jungling is not punishing people who don't have flash up hard enough, and instead opting to just farm my jungle.
Second tip: know your limits with ganking. Don't try to gank bot lane when they have all summoner's and your lane is pushed toward the enemy tower because an Infernal Drake has spawned. If you think you can, try to solo it. If not, tell your bot lane you'll come if they let the enemy bot lane push. Tell your bot lane to take a trade with them to try to get them to use something before you come, then disengage, and you'll go after they've used it, while they're overextended with no escape.
Final tip: know when it's best to take objectives. If you kill the enemy bot lane, that dragon should be mostly free unless the enemy jungler comes to try to smite fight you. If he does, you and your bot lane can easily turn and kill him, and even if mid lane comes, you're still 2v3. Don't be afraid to tax when you gank a lane, but know how to do it right: don't tax if the laner is behind, never take the cannon (unless you're trying to push to take the tower), and only take 3-4 minions, then leave. Know when you can try to shove down a tower. Using bot lane as an example again, bot lane tower doesn't have the Fortification buff that the other towers have, so it's a lot squishier than other towers; a successful gank bot lane with a full wave for your team and another well on its way could easily take that turret, especially if you're an AD jungler. This should give you turret first blood, and if you're still healthy enough, can easily be chained into a dragon. But don't give up a gold lead for a dragon; that Ocean Drake isn't worth your gold lead.
For support, I'm an ADC main and know what I like to see in supports.
First, never stand behind your ADC unless you're low health. It's equal to or in front of them so that, if someone tries to poke your ADC, you can easily put some damage back on them. Run hybrid pen reds because, early game, your autoattack damage will hurt just as much as your ADC's. Don't be afraid to tank a bit of poke so your ADC doesn't have to, and don't be afraid to poke the enemy lane back. You should have 3 potions compared to your ADC's 1, so unless you're a strong healer like Soraka or Nami, you can heal the damage back up from poke a lot better than your ADC can.
Second, know when to go in. I've been finding a lot of supports lately who just mindlessly go in and feed kills to the enemy bot lane for no reason, even when it's completely stupid to. If you're going to get level 2 faster than the enemy bot lane (entire first wave and 3 melees on second), don't be afraid to engage a level 2 fight, just be sure to ping first before you go in so your ADC knows, and if he doesn't look like he's following up, disengage or don't engage in the first place. At this rank, not many people will know how to abuse the level 2 powerspike, however, I've had it done to me and I've done it to others. The other thing for when to go in is look at the enemy ADC's AD, look and yours, try to think how much damage they provide, and try to think how much more (or less) damage you need to kill the enemy bot lane. Also, always look at your ADC's mana before going in. I've had people go in when I don't have the mana to back them up, and they usually wind up either flashing out or dead. Don't go in if your ADC has I would say below 150 mana. Most ADCs can use their full rotation on 150, but some (like Miss Fortune, Lucian, or Ezreal, who rely on their spells for damage a lot more), will need at least 200 mana to fight.
Third, don't be afraid to poke (if you have poke). Simply put, if you're a Karma, Brand, Annie, Anivia, Lux, Bard, Nami, Janna (shield and auto, the W I think it is? Zephyr), Vel'Koz, Zyra, or any other support who has good damage from range, USE IT! It's a lot easier to kill an ADC when they're on 300 and you're on 600 than it is when you're both on 600. Just make sure that, if your opponent is a poke-based champion too, they won't be able to poke you back (example, Brand vs Karma: the Brand pokes the enemy ADC with W and E while behind minions so the Karma can't return poke him). And yes, I know that Annie, Anivia, and Lux aren't often seen support anymore, but they were once very good meta supports.
Fourth, don't be afraid to ping. Ping when you want to go in, ping when you want to back off, ping the wave when you want to push it, ping away from the wave when you want to let it push. Ping, ping, ping. Assume that you're smarter than your team and hope they'll listen to you. If you ping before going in to fight, it can tell your ADC/the lane you want to gank, "hey, I want to do this, I think we can kill them." And it gives your ADC/laner time to ping back to say "I don't think that's a good idea" or "that's a great idea, let's go do this." Communication is one of the most important things to use to win games, so use it. Ping your health/mana bar to say "I'm low, let's not fight" or "I have enough mana to do a full rotation, we can do this." Ping your EXP bar to say "I'm about to level up, we'll be stronger than them when I do" or "they're pretty far above me in level, let's avoid fighting them for now." Ping your gold/the item you want to buy in the shop to say "hey, I have enough for my next item, let's push this in and back" or "I'm pretty close to my next item, maybe we can fight them and get me enough."
Fifth, this one being back to just support, don't leave your ADC alone in lane. A lone ADC, especially in a pushed lane, is prone to getting grabbed and killed. Now, I go alone in lanes a lot mid game to split push, but this is playing Twitch and I've warded up everywhere they could come from to kill me; they can't get to me without me stealthing and walking away. However, you should almost always be just following your ADC around unless they are a Twitch using this split push strategy that I use to help me catch back up if I'm behind. They come for a splitting Twitch, and, if he's been smart about his warding and he's paying attention to his map, he should be fine. However, if you're there, you'll be dead. If he hasn't been smart about his warding, you go around and ward and ping him if you see someone on the map.
Sixth, roaming is generally bad. This is continuing on the last point of not leaving your ADC alone in lane, unless the enemy bot lane has pushed it in to your tower and backed, it's generally bad to go and roam. If you're Bard, do something when you roam. Put down a deep ward, gank a lane, do something other than grabbing chimes. And leave right when you know your lane opponents have backed. Playing support is all about pressuring the enemy bot lane, and leaving in a lane where the enemy has pressure on yours or standing back and doing removes all pressure your lane has. You just existing and standing in the right spot could mean that they don't have kill pressure on your ADC.