So important how you do your research. Too many just chase after whatever is hyped as the next big thing. Then they throw their money at it without any real understanding of what they are even investing in.
One thing I've found particularly useful is to get involved in the community for each investment you choose, via Slack, etc. By following them over time, you get a good feel of what's going on. It takes some time each day to stay up to date, but can make or break your decision to keep holding.
This is especially true in cases where the team itself is heavily involved in their community. In fact, I would almost consider that a "must have" as it allows you to get a good feel for who is behind the project and where it looks to be going.