To invest in crypto effectively, I will see the concept, prospect, the progress, and the risks. If they have the good concept, prospect and progress of the coins, I will invest in the coins and then hold them. Additionally, the good altcoins with the good volume and progress are better to invest, too. However, in this case, I will only buy the coins that I can afford and be ready of any risks. Just don't follow the hype. Analyze by yourselves and afford as you can.
Actually day trading is more effective to make profit rather than just hold for long time but this is belong to everyone choice about this. But for day trading, its not that easy to do it. Only person who has good knowledge and experience in this field can do this to avoid massive during trading.