Dying to the jungle creeps, help!

Hello, I'm quite new to the game you could say, but I do watch a lot of vids though etc trying to learn what to do. As of late, I've been trying to learn to jungle. Seems no one really cares about helping gank the lanes and if I'm top 99% of the time the fellow with me never shows up or leaves soon as he hits level 6 and never comes back, which makes me have to 2 v 1 and I never can get anywhere with that. So I decided it's time to learn to jungle because at least then I can actually help suppress the opposing team from leveling. Especially after I was in a bot game yesterday where I was forced to go top and we lost to a freaking bot team because my team would not grp or defend the lane. I even had 26 stacks of dark harvest and I just could not do a solo push with Galio.

Anyway, I have become quite frustrated that I can't seem to clear the first 2 camps (Red Brambleback and stone crabs) without dying half the time, and I always die if I live past those two and go for the Raptors. I've been using the practice tool to try and figure this out. Since I don't have many options and Master Yi seems more on the easy side to understand I have been using him. I don't get it though I watch vids of ppl clearing the entire thing and still half health while I have burned two pots and a smite charge or two and still end up dead.

Seems some of the vids though are out of date that I have watched though since they seem to be able to do a shuffle back and forth to get Brambleback to turn back around so they can keep hitting him and take minimal damage, If I try that he ends up just stomping me and he will keep following me, he does not turn around. Even after that though the stone crab guys go down pretty easy in the vids they don't seem to even have to move when they are fighting them, while me, on the other hand, they beat down pretty quick and if I don't try to kite them or use smite this is where I usually end up dead.

So does Master Yi, have some kind of trick that I'm not getting here? Or is there something I am missing? Some kind of trick to avoid the damage?