Note that ships get slower as they get bigger and more powerful, and that bigger guns have trouble hitting smaller fast ships, so you have to consider this and your fittings when deciding which ship to take into combat.
This diagram from EveMon shows the skill tree required to pilot a Dreadnought, which is a seriously expensive ship designed for large-scale warfare. (Get your copy of EveMon from here).
You can see that to pilot a Battleship, I need 6D (six days) of prerequisites before I can begin learning Battleship skills. To start training to pilot the Dreadnought, I need 112 days of training. You can see that completing Level 1 training in the Dreadnought itself will take 2 hours, and that the skill book would cost 100M ISK. You'll see that I already have sufficient Spaceship Command skills to fly a Battleship, so don't need to learn them further.
The training time for the capital ship weapons you need for a Dreadnought to be fully outfitted would take a comparable amount of time.
It will take a full years' training from noob to being a capable capital pilot.
Most pilots learn how to pilot a Battleship, then stop, and focus on weaponry, warfare, trade, corporation management, or specialised ships such as Assault Frigates or Interceptors, etc.
Capital ship piloting is a career choice in its own right, because of the time investment required. They cost at least 1B ISK to buy a Freighter, nearly 2B for a Dreadnought, and the weapons cost 50M each or more. They're for specialised purposes in PvP.
See this page of my blog for details on ship race choices.
Remember, you can learn any other race's ships - they're just another set of skills. Of course, that is very time-consuming.
Really useful skills to fly a ship properly
Skills useful for all ships.
Very high priority - should be trained to a minimum of level IV.
- Electronics (fit more stuff)
- Engineering (fit more stuff)
- Energy Management (more capacitor)
- Energy Systems Operation (cap regenerates quicker)
- Shield Management (more shields - harder to kill*)
- Shield Operations (regenerate shield quicker*)
- Repair Systems (repair armour more efficiently*)
- Mechanic (more structure - harder to kill)
- Hull Upgrades (fit better armor - harder to kill)
- Navigation (fly faster)
- Evasive Maneuvering (turn quicker)
- Warp Drive Ops (warp farther)
- Spaceship Command (turn quicker)
Skills useful for combat ships.
High priority - train to at least III:
- Drones (use drones)
- Scout Drone Ops (use combat drones)
- Drone support skills
- Long Range Targeting (target farther)
- Signature Analysis (target quicker)
- Targeting (target more ships)
- Energy Grid Upgrades (use PDS, RCU)
- Gunnery/Missile Launcher Ops (see above)
- All Support Gunnery/Missile skills (as above)
- Weapons Upgrades (fit more stuff)
- Advanced Weapons Upgrades (fit more stuff)
- Repair Systems (even if you shield-tank, this lets you use repairers, then don't have to pay to repair)
- Acceleration Control (go faster w/AB/MWD)
- Afterburner (go faster)
- Fuel Conservation (use less cap)
- High Speed Maneuvering (use MWDs)
Add to these the prerequisites for the ship you want to fly and the weapons you'll use (for example, Tech 2 equipment is a good aim too) plus the tanking skills, armor or shield, and you're set to start using them to their fullest.
(Sourced from this thread).