Hi op,

For me I buy altcoins whenever I like the project and I see value into it. Like if the project will help
human to their current problem like privacy or etc.  Also, I am looking for an altcoin devs that are actually passionate in their project.
Because they need to be the first one to believed in their project and if investor like us saw it from them, then it is a great sign that it will not turn out to be a shitty coin.

With regards to your technique on buying, yeah listing gives a good price impact but after being listed it will plummet.
it's like buy the rumors sell the news. If there's a way for you to know a listing prior announcing then that would be profitable but if you just go
with the hoards in the twitter I think you will just lose some. But if you believed in project then movements will not hurt you at all.