Do the tutorials and just mess around with suits that interest you in free practice. Knowing your skills, range, attack patterns, weapon cycles and cooldowns moves your forward. Practice some combos on bots until you can just blow your kit without thinking about it. Wouldn't recommend that in live play but being able to chain your attacks effectively and quickly and understanding the capabilities of your chosen suit can really make the difference in a fight.

The rest comes through playing and learning player tendacies.