When you first start, it's best to decide what strategy you want to play. A list of strategies can be found here:
http://galaxylegion.com/wiki/index.php/Ship_StrategyThat ^ is the galaxy legion wiki, and has alot of information on it.
If you decide to go for combat, put most of your rank points into weapons, hull, defense, scanners and planetary buildings. Let your cloak and energy techs fall behind. Shields are a must for planetary production, but you should probably leave that until later, and skip to mass shields.
By rank 50 for PvP you should have:
Graviton Shearers/Disruptor Cannons
Quantum Capacitors/Antimatter Reactors
Magnetic Deflectors
EM Absorbant Panels
Durtainium/Microgel Armor
Inertial Dampening/Spacial Thrusters
Multiwave Sensors
Nano Assembly/Deep Extraction
Advanced Logistics
Your shield, cloak, and base trees can catch up later on. By rank 50 you should have a fair idea of what works and you'll be able to judge it yourself.
If you need more help, PM me here.
~StrmAvenger
Rank 85
Top 50 PvPers.