By crypto's you are referring to the ICO's I guess, and yes they are huge in numbers and come like crazy everyday. For better understanding of them you can always go through their white papers and roadmaps. Just know that fake whitepaper can be made so check for the plagiarism first this is most basic way to look at it and just to be sure that its not copied some where giving the indication of scam. If you are good there then understand what is in there and are people talking about it over the forum. If you see good amount of buzz and good response from the community then you can choose such projects. But at the end you never know what will happen and all these are just underlying principles to choose the fittest one.