How do I stop sucking?

I've been playing league for a while now, like three years or something, and I noticed recently that I haven't been getting much better. I suck at the game. Like really suck. It's not how I build, it's not my masteries or runes or ability order, and its not that I don't know the basic starts of the champs. There's something universal about it. For example, the last game I played, i played as against a teemo and got destroyed. Here are that game's stats: http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2527040259/209131552?tab=overview First blood was scored on me, and I noticed after the second time he killed me that I needed to stay away from him. But at the same time, I didn't know how to do that without just letting him dominate the game. i ended up 3/10/1 and my lane opponent 11/0/1 The game before that (sort of, there was another game where my team surrendered after 3:24) I played , and I kicked ass. I purposely avoided getting kills so my adc could get them, and still went 5/1/10 against a and a . Here are that game's stats: http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2526953286/209131552?tab=overview Maybe it was because I didn't chose when to engage, but that game was definitely easier. The game before that, I played again, and went 13/5 laning against a . maybe it was because of first blood, but I did really well that game (well… sort of). Here are that game's stats: http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2526877184/209131552?tab=overview Does anyone know what I could be doing wrong? I never know how to stay safe from my opponent, and I don't want to sit under my tower doing nothing (I mean, it's not that I just don't want to be board, it just feels like a worse idea) all laning phase, so I either get kills and get huge or I die and start to feed. Any advice?