Research it takes a few days/weeks so if u're in this fase take your time.
1.Forum search about the coin;
2.Join the telegram group and try to interact with the members;
3.Try to make a post on the forum and also see the crowd sentiment;
4.See some data on coinmarketcap.com , : https://icodrops.com/ , https://icorating.com/
5.Watch this tool from investing.com - find here the explination: https://bitcointalksearch.org/topic/m.29503403
**LATER EDIT:
6. Team - research moust of the members on linkedin and google , also the backers or advisors.
Doing this can be of help to get a sense of a really good buy... at least this is what I do.
What are your thoughts ? How do you do it??
Cheers!
Nice advise but what can help me more easier is the ICO ratings of a certain altcoins. Where I don't need weeks doing research and days are enough. We don't need a lot of time just to buy altcoins, I think, 3 - 4 days are enough for us to make research. But all in all, you got a great advise.