What is your best strategy to see if the coin will be profitable or not?
I'll try to give you important aspect regarding the critical point to choose the right coin to be your investment.
1. Dev = Expertise dev gives a support for the market.
2. Clear roadmap
3. It's not a dumbass idea (I mean about the innovation of project).
4. Not related to ponzi scheme.
I saw that good method is to read news,forums about particular coin, but which websites to check, what should I look in the articals, news?
Usually, a lot of people just try to get the latest news from the announcement thread.
It has contained the various source for you about the latest update nor news of the coin.