Jungle practice

Just ignore the people that freak out and dont let anything they say get to you there is no other way to do it... Maybe for a while until you feel like you have gotten good enough for your liking in jungle just turn the chat off in game and play or just mute any toxic players

If the excessive scolding of your peers truly proves itself to be overwhelming, you could even try to jungle in a Player vs. Bots game, just to practice your routes and strategies.

Play with your friends that can cover for your mistakes, that way they can make up for you if you mess up! :)

Essentially what they said. Unlike the other roles, a few tips aside, jungle is a role that you can really only learn through continuous play. Mechanics are still important, but you'll need to develop a jungler's intuition which comes from raw experience. This is the difference between a jungler and someone that simply plays jungle.

Keep in mind, since it's the only role with the flexibility to roam the entire map( as opposed to having a dedicated lane), the role itself carries a pretty good amount of weight and as such has become a key target for blame. When players lose their lane, the first person they'll look to blame is the jungler for not pitching a tent instead of taking better opportunities elsewhere. What I'm trying to get at is taking heat from other players regardless of how well you perform is something that'll happen often even if you do well, which kind of sucks. That being said, don't give their words too much weight that it gets you down (which is much easier said than done, I know). If someone is becoming overly toxic, mute them at the first sign and continue to practice how you normally would. Lanes usually think about their own best interest, which is normal but can sometimes contradict what the jungler's or whole team's best interest is.

http://www.twitch.tv/nightblue3 is a really awesome stream for players wanting to get better at jungling. He was my goto person for Hecarim play. Other than that, try to find someone who does fairly well in the jungle that you can queue with, maybe a friend like SirTezla said, or just anyone willing and let them have jungle role so that you can have their commentary via Skype/Phone (or the other room xD) as opposed to randoms playing the role in-game.

All really great advice! Thanks guys!