Don't ask for advice like this. People are just going to shill what's in their bags. I would focus on research, research, research. If you're not willing to put in the time and hard work, then the safe bet is Bitcoin. Based on the historic trend, it's always a good conservative choice.
But if you're looking for bigger gains, you need to put in the hard work. The altcoin space is rife with scams, pump-and-dumps, and vaporware. You need to get to know the space and learn to quickly filter out the scams. Successful altcoin investors read ANN threads everyday. They keep up on fundamental news, they calendar fundamental events (roadmap dates, software/feature releases). They research coins all the time -- old and new.
Find coins you like fundamentally, then analyze the supply/income generation (staking, masternodes, etc)/marketing capacity/other fundamentals. Study the charts. You should probably invest in increments -- over weeks and months, not all at once. That will help you minimize the drawdown (the unrealized loss on your holdings).
There's a learning curve and it takes some experience to get there, but you need to learn this game on your own. If you go off coin recommendations on forums and trollboxes, you might get a good call here and there, but you'll probably lose everything eventually. It'll be much more valuable for you to develop an investment strategy which works for you. I think you'll find this will pay off over and over as the years go by. Good luck.