Research the whole market and find some coins for your investment. I prefer to invest in altcoins, because I think that BTC would be replaced in the nearest future. So pay your attention to such coins as ETH, XLM and NEO.
we all never know whether bitcoin can be replaced or not. the problem now is that the bitcoin situation is starting to improve again. so I think even though the altcoin is progressing but bitcoin is still the market leader