There is a lot of for us to know when the us the right time to buy a cryptocurrency , many people have list to be considered that they need to see first because they buy a coin and for me Im waiting to the good news of the project of the coin so I can buy because news is powerful and for sure it will have effect on the price of the coins but if it's bad news the result is not good also if the news is legit.
Actually news alone is not enough because most of the times there are paid articles with fake news promising big times in the development while actually the team is only planning to get more investors and then the coin will just slump down.
I think one must know the team members and the working developers well to know if they are capable of doing what they promised and if the token is doing an ICO then make sure the whitepaper is solid and not just a money earning machine. Because of the time you can see from the whitepaper that the coin is promising big things which are too good to be true and avoid such coins totally, unless they have some backing from good developers or known members of the community.