Try other networks. You want a variety of offers anyway so apply to as many as you can. Sometimes affiliate managers are to busy to go through applications in great detail, so if you talk a good game and make yourself sound like a pro you can get in.
If you have any affiliate marketing experience and have some sort of offer/sales page then show it to them. If you do not have any affiliate promotions then start one. Go to clickbank and find a product and put up a page. Tell the network that this is an offer you are running(although you are not) and you set up campaigns depending on the offer.
You can say something like this, "We have extensive experience with affiliate marketing with a concentration on ppc and media buys to generate traffic." You can add more if you like.