New to Vaping, Help?

Guys im new to vaping, just got a starter kit for 20$ 4 days back, i wanna start vaping to get rid of my chewing tobacco habit, i know i may sound ridiculous but for past 4 days i didnt had any chewing tobaccos, just vaping :D anyways, i have few questions, what are the healthier e liquid's out there? i dont wanna get sick from vaping (duh), and are there any liquides to makes to consntrate more? like caffine ? that dont have side effects.

Thanks