On closed shapes, pick a spot with good angles and good visibility. Fuseballs ride the lines. The safest place to be is in the space next to one. It looks like it will kill you, but the hit logic only tests the center of the fuseball. Watch out for fuseball tankers at higher levels that split into two fuseballs that will immediately try and jump on you.
Pulsars are only dangerous when they are pulsing.
Listen to the low, periodic buzz sound. As you get used to it, you will find yourself adapting to this built-in rhythm. You can shoot them when they aren't pulsing or spin out of the way. Watch out for pulsar tankers at higher levels that split into two pulsars on either side of the tanker lane. Regular tankers contain two flippers.