It has become more and more obvious to me over the years we've been exploring polyamory that one of the primary skills that is helpful to enjoying poly relationships is partner selection. This sounds like a no-brainer. Of course it's going to be a good idea to choose carefully who you decide to be involved with! The realities can be a bit murkier, with such factors as physical attractiveness, also being poly, sheer opportunity, and a desire to fill a role, skewing common sense and realism.
Let's say, for example, that you meet someone who you really connect well with! They're witty, funny, cute, poly, have their stuff together. One small problem: 90% of the time, your schedules aren't going to line up. Unfortunately, unless you are willing to change your life to accommodate a new schedule, this isn't likely to get off the ground floor.
Another idea: You are really jazzed up about the idea of meeting a hot bi babe/boy. There are lots of fantasies that work really well by being able to insert this fictional person into your life. You meet someone that fits the bill! They are the HBB! Let the rejoicing commence! Alas, in your zeal to enjoy the fantasy, you forgot to look under the hood and notice the lack of a productive life, that they're a smoker, or that they don't like kids (which you have). Your fantasy and reality don't belong in the same space.
You're at a community event, you meet another poly person who can relate to many of the factors present in your life. What a great thing to be able to talk and share with someone that understands! Unfortunately, you don't really have anything else of significance in common...
Perhaps most challenging of all: You meet someone that you REALLY connect with. They click with you, and seem well-suited to becoming part of your circle. Unfortunately, one of your other partners has formed an instant dislike of them, or they don't seem to get along with someone of significance in your life. Do you proceed? Do you back off? Do you move slowly and hope they start getting along?
So, how does one go about selecting a potential partner? Part of it is putting yourself in places where you can meet new people that might be amenable to poly, part of it is being brutally honest about your own strengths and weaknesses, preferences and blind-spots, part of it can be listening to outside partners who might have more perspective on a new person than you do, as you peer through your rose-colored glasses. ;)
When I first started my business, a good client was anyone that would show up and pay me. As time went on, I learned more about the types of people that were enjoyable to work with, and the types that were not. My marketing changed to reflect those preferences. In the same way, it is important to continue to rifle your approach to exclude those that won't make good partners from occupying the majority of your focus. There will be people you meet, you like, you feel attracted to, that are better left as friends, not brought in as partners.
One of the criterion I am currently working on developing is to focus on potential connections that have chosen to have significant responsibilities in their life. It seems to engender a more responsible approach to life that fits my relationship style better. Someone who has set their life up so they could drop it and move on within a week isn't likely to have the stability or maturity that I enjoy in a partner.
Time availability is another concept that I look at. If our schedules aren't likely to match up approximately weekly, this isn't likely to be a deeply connected relationship. People that reach out to me about as often as I connect with them are great! Me doing all the chasing and planning isn't fun, at least once the first blush of NRE wears off. ;) I enjoy people that have a good healthy relationship in their life already, since, with two full-time relationships already, I don't have the resources to take on a third person who looks to me for the majority of their emotional needs.
There isn't a list of qualifications you must possess to make it past the first round of interviews, but there are things that will limit the development of a relationship, or cause it to fail pretty rapidly. In the interests of not wasting the time of others, or myself, it is helpful to know my deal breakers, be able to share them, and be able to tell myself "no", even when I _want_ someone, despite recognizing a lack of suitability.