Honestly, a good trader also experiences to lose their investment, all here in cryptocurrency are risky you must be smart and don't believe in any promises.
The only coins that I could suggest you that can reduce the risk of losing your investment is to choose the coin, which is mostly used by many people or choose a coin, which is on the top 10 in coinmarketcap all of them are less risk than you are investing in new ICO's or new coins because it's too risky so avoid investing in them.
Also, make sure that you can control your feeling when the price is decreasing because there are still chance that the price can recover back in the future.
excellent advice