Hi, Diane.
If you're going to focus on becoming a more successful Affiliate Marketer, that also goes a long way to helping make you a more attractive JV Partner. You should decide whether your focus is going to be building email lists +/or feed subscribers (which are both a given as far as I'm concerned) and what methods you're going to use to drive traffic to your subscribe forms and feed links, and just as important ... building a relationship with your audience as it grows while figuring out the right balance of free and promotional content delivery. As the size and responsiveness of your list(s) grows, and you become more of a factor when promoting potential JV Partner offers, you will be qualifying yourself. Once you have a product of your own (if you decide to go that route), you should have far less trouble securing support from JV Partners you've aided on launches in the past.
I realize the aforementioned is a very general response with little in the way of specific advice, but we have to start somewhere ... hope that helps a little, for now.
Cheers,
Mike Sr