First thing you should do is begin monitoring the highest rated coins on most people's lists and research all of them in depth to see which one feels right for you

Other than the obvious candidates like ETH, XRP, LTC etc. My personal ones to watch are ones like TRX, XMR, WAVES, NEO, LSK. That is my personal opinion on a few but you'll probably uncover a lot more after in-depth research.

Good luck investing