Starting Out
Starting at your buffs is a thing from season 4. It just isn't as effective anymore because it puts your teammates behind and the gromp bonus is just too strong to pass up (and if you are playing something like sej, udyr, etc. then it will be one of your strongest buffs all game long). After you clear gromp you should place a ward at the entrance to your jungle. This will prevent some nasty lee sin or shaco from walking right up to you and getting an easy first blood. Get your blue then head over to the wolves and clear them.
Something important to remember is not to use any of your health pots if you plan to back after the wolves. I haven't played all the junglers (just started playing this game September) but as long as you don't stand still while you are clearing your buffs, you should be fine. However, if you plan to keep clearing, use them to your hearts content. As to when you should keep clearing or back, that's up to you. A general rule of thumb is to not back if you think someone will take your buff, and to instead catch them out at it and maybe kill them. However, from what I understand you aren't the best clearer, so you should almost always back after 450 gold and level 3 (that's what you will have after three camps).
As for starting on the red side, start with krugs, go to the chicken camp (something most people don't do, but trust me, it's a thousand times better), clear the little ones first (it'll save you a but load of damage) then go to red buff and smite it (why clearing chickens second is better). You can ward the bush leading to your red, or the one behind it depending on the person you are playing against. If it is someone with a gap closer, like lee or shaco, place it on the other side of the wall, then check the bush leading to it. Usually you don't have to back and probably shouldn't because red buff is a powerful ganking tool, especially this early.
Clearing scuttles is possible after this, and/or ganking. Really, only do scuttles if you have some form of cc or a lot of damage, because if you don't it could take too long to really be considered efficient. Good early scuttle takers can be xin, udyr, lee, etc.
Which buff you start on should depend on the game, as you should almost always be going BOT lane, not buff lane. This is because you get a stronger leash, thus taking less damage and getting a faster clear.
When you back get a 
until you get better at clearing.
Invading
If you plan to invade, make sure you know which buff they are going. This means you will have to get balsy and ward their jungle, but if you don't want to do that just know they will almost always go bot lane. It's just standard.
You can invade with almost any champ, but certain champs shouldn't like amumu, or sej, while others like udyr or lee sin can pull it off incredibly easily. Pay attention to who the enemy jungler is as well. For example, if you are playing udyr and the enemy is eve or sej, just invade that bitch, get a free buff and first blood and walk away like a boss.
Pay attention to the laners, because in some cases they will come to kill you, which means if any enemy laner is missing DO NOT CHASE THEM. Go to their buff, take it if you think you can, then walk out. Doing that was a enough damage, the kill is just helping a bit, but it certianly isnt worth dying for.
Always know where the enemy jungler is. If he goes top lane, take his bottom jungle and/or buff. If he goes bot do this top or gank another lane, or countergank. If the jungler is top lane that is a prime time to take dragon as well, especially if the mid or bot laners are missing, and even if they aren't, you have smite advantage, which means it's YOUR dragon.
Ganking
If you have an ult reliant champ like Warwick or amumu, gank whenever it is up. Otherwise, ganking is probably a waste of time and gold, so don't do it. Junglers like Lee Sin, on the other hand, are gank reliant. You should not die as these junglers because it will set you behind, a lot. They are also champs that will snowball really hard early to mid game. So get a kill.
Pay attention to the map. As a jungler, and as a laner, your eyes should always be on the map unless they don't need to be. If you pay attention to the map, you will know when lanes are gankable or if they will be gankable in the next minute or so. If the enemy laner is pushing, thats a good time to gank, if he is low at turret, thats a good time.
Set up a jungling route. This is why you are falling behind, because you dont path right. If you get this right, you will have so much more cs and be at least a level ahead of your bot laner (should be a goal). What I mean by pathing is think what camps youll go to before ganking or invading. As a jungler, something comparative to 70cs at 10 minutes is 80cs at 20 minutes. To get this you need to have at least covered and pushed out a lane once. This goes back to map awareness. If you see one of your teammates backed, clear and push out their lane, if they enemy has backed and they want to back (are oom or low) then help them push to turret.
You do this right, you will have cs and outlevel almost everyone, depending on your elo. Farm=fed, dont let any of your laners tell you differently.
Tips?
Focus on a thing. What I mean is, invade, gank, or farm, or you will fall behind. If its a tryndamere jungle and you have udyr, invade; if you have ww, farm your ass off and have devourer by 8:30 at least, or get cinderhulk.
You should be objective based. If you pay attention, you can easily have a mid turret by at least 15 minutes if your good enough. By doing this you can also get the enemy jungler to reveal themselves if they want to cover lane, being extremely useful. You can see what buffs they have, and see where they go afterwards, setting up a possible invade.
If I think of anything else I'll try to edit the post. First time I've done it though, so I don't even know if that's allowed. We;ll see.
games. If you're looking to learn how to jungle, don't do this. 
