I think the best crew are ones that fit in personality wise with the skipper. If there isn't that "fit", all other things are not important. Example if the skipper (you) and crew member just don't get along, having someone crew for you that is the most skilled sailor isn't worth the aggravation.
If you are a competent sailor/captain, there should be no reason not to take on a green crew member for your voyage if you have the patience to help teach them the finer aspects of handling your boat. That being said, you really should not take on anyone that hasn't at least been sailing or boating a few times so that they are at least familiar with going out in coastal waters for hours.
If you are a newbie skipper, you should look for folks that maybe have more experience sailing than you do and then learn from them.
Several skippers that I have crewed for had a 1/2 h or so phone screen before I was invited on their boat. Basic questions like sailing experience, type of work I did, hobbies, etc., would give them clues into whether I would fit into their "organization" that would include other crew members.
If the potential match was there, I would be invited out for a sail and "evaluated". Also, I would evaluate whether I wanted to remain a crew member after the trial sail. At the end of the sail, if I was interested, I'd asked to be invited back. It would be pretty apparent to both parties if the "chemistry" just wasn't there, and this has happened to me also.
So my advice is to do the following:
- Advertise for crew and with details of what would be expected and what you would provide in return.
- Once you get names and contact info, do a phone screen and talk to the potential crew folks about what you are looking for and ask them what they are looking for, hobbies, interests, sailing/boating experience, etc. Solicit information that may help you ascertain whether or not the individual will "fit".
- Of those that you think are worth a second look, arrange for a great-n-meet sail for a few hours to get a better feel of the skills and personalities. Not only do the crew have to get along with you, they have to get along or at least work tolerably with the others.
Once you have had your meet-n-great sail, invite only those that you think will good.
You could ask for sailing references for their sailing skills, but unless you're paying them, I think that is not really the best foot forward with building relationships.