I play and have played league for a long time, let me say if you are in silver, playing jungle is like committing suicide. Don't do it. I've mained mid for a really long time, so here's what I have to say to play mid well.
1. Don't be a pussy, learn each champion and how they play. Don't all in with brand if you didn't land a stun already, and don't play passive farming leblanc unless you're getting zoned. Learn how to perform in your lane in regards to champion play style and you can come out ahead.
2. Probably the biggest problem I see is people feeding mid then going "I'll just farm!". No. He'll just dive you. If you're getting shrek'd early, farm and play passive under turret until around 6 - 9 then go roam and snowball the shit out of other lanes and just leave your lane. If they get mid tower, you can then farm more safely and they have to overextend further to farm if you can freeze the lane.
3. Teamfights: Don't play like you're the tank, because they will focus you. If you are ahri, don't go balls deep on graves because he is "their carry". Everything is situational. If your adc is mega fed, then you should consider peeling more and trying to damage/cc the assassins and tanks more. Play the teamfights to help your team win, not for the kills or "focus".
4. Most importantly, learn how pushing works. If you push your lane and sit around waiting for your chance to farm again, you're gonna get ganked 9 times out of 10. Here's a trick, push the lane, then go roam/take jungle camps! Don't sit around just hoping they will try to go in on you or thinking you can 1v2. You probably can't. Also, if they push to your tower, then roam, if you DON'T follow, PUSH the shit out of mid lane until someone comes to stop you. Buy wards too.
5. Don't play shitty champions.
6. Play the shit out of broken/good champs in the current meta: (Malzahar, Gragas, Leblanc, Yasuo, Kassadin (LOL), Brand, Ziggs).