1. team behind the project?
2. type of blockchain?
3. real-world use-cases?
4. partnerships?
4 points above is what I always see before investing in altcoins and besides that I also see whitepaper so that I know more about the objectives of the project
for new projects might always pay attention to that. but for old projects that are already large in the market, I think that only the market demand and analysis plan will be considered shortly. Even the day trader probably won't pay attention to that. what they think is the volume of trades that occur.