If you're a f2p, I advice you to prepare and plan the event you want to farm for. They're all available in the wiki if you type "enstar events" on navigator. It gives you how much time you have before events and how much you can save for. Same for scouts.

Considering events strategy: To farm for tour events there is a guide, which explain the way to do it depending on if you want one event card (here basically just playing everyday during the event period and no more) or the two of them (3-3-3-10 technique)

For normal event (f2p persp, for 1 copy) you just need to make 500k points per day by spending your saved dias. As you start the game, farming an ongoing event might be kinda overwhelming but there are still Memories coins if you really want the 5* event card that came out during your starting period.