You cannot defend your wormhole or your POS if you are not there. It does not matter how well your POS is setup, a smart attacking force can take it down. To successfully defend any territory in Eve you must have multiple players in your corporation/alliance that are committed to staying.

When selecting who gets into your high profit wormhole and who does not, you must strike a balance between two major things. You must balance the "need for Defense and Presence" against your "need to make ISK". For a general rule of thumb, bring a minimum of five players. These players must know scanning, mining, PvP and a lot of game mechanics. For every one skilled player you can have one unskilled player. You must be careful about how many new players you let in as they can cost you your wormhole if they are the last man standing. You must trust all of them. Corp members are not protected from other corporation members in the game of Eve. If you have doubts, don't invite them. In addition, everyone should know why they are in the wormhole in the first place. Is it profit or a pirate platform or something else entirely? Be ONE on that.

So, as this applies to wormhole defense and colonization here are some things to look for when selecting wormhole corpmates:

1) What time zone they play in. You want a good mix of US and EU time zone players. When one side of the Earth is going to bed, the other half is getting up. The goal is to have someone in your wormhole 24 hours a day, seven days a week in order to spot hostiles or undesirable wormholes.

2) How often do they play? It does no one any good to have corpmates that you must rely upon if they are flaky about when they can log in and how long they can stay. I'll take the 4 hours a day guy over the 30 minutes every other day guy any day. The ideal candidate is a level headed person with no job that stays logged in forever.

3) Those with PvP experience. Not all of your corpmates need to be natural born killers, but some of them do. PvP in Eve is not something to learn while your POS is being taken down in front of your eyes. Try to mix PvP and PvE players. The PvE players will provide muscle power for the PvP players to flex under stressful conditions and the PvE players will be the ones running the money making processes.

4) Consider the all important issue of unit cohesion. Nothing ruins a game like having a player who acts like a complete idiot. If you want a good defense then make certain that you will fight the enemy and not fight amongst yourselves.

5) What ships they can fly. This is rather important. You want all corpmates to be able to fly something that can contribute to fending off hostile players. Eve is intentionally setup to have a mind boggling array of ships and modules to choose from. The rule of thumb here is variety. The more ships you can choose from the more likely it is that you will be able to exploit a hostile fleet's weakness.

6) There is strength in numbers! Skill aside, it's hard to kill 30 ships with just one ship. This is really the heart of Presence within your wormhole. I hesitate to give you a minimum for defending your hole, but I'd not be caught dead in a hole without at least 5 pilots at the ready. Try to base this minimum amount by considering the maximum size of an incoming hostile fleet in terms of mass. Do you want to be 1:2 or 2:1 in terms of ships?

7) Consider who your Directors are and the leadership roles. This goes to corporation structure and organization more so than to wormholes, but it is very, VERY important.

You should have at least one pilot with the ability to do everything. At least one (preferably 3 or more) to be able to do anything POS-related. This person also needs access to funds and be able to trade independently of his K-space counterparts. Remember, you are an island so you must be as self sufficient as possible.