Two n00b-tips for playing in open:
a)Never, ever fly without enough cash for a rebuy (you can check the amount needed on the right-hand side MFD)
b)If interdicted by a player (CMDR prefix, hollow square/triangle on the radar), throttle down immediately, select another system in a meantime (unless you're too attached to your current one). When you drop to real space, boost and jump to a selected system (high wake jump) as soon as possible. The spool-up of an FSD during real space-supercruise transitions (also known as low wake jumps) is slowed down if a ship of sufficient mass is in proximity, but the limitation isn't there for inter-system jumps.