Getting back into the swing of things

I started playing league back in 2012 and stopped playing some time in 2013. In that time, I made it to lvl 30 by pretty much only playing bots and I never played ranked. I want to start back again but I'm not as good as I used to be and I'm afraid I'll start playing with people whose skill level more reflects a lvl 30 player while mine is much lower. What I'm asking is does anyone have any tips as to how I can gain my skill back without having to make a new account or just losing over and over in lvl 30 lvl pvp. Anything helps, thank you.