Try "hey I saw this really amazing thing the other day and it is sooo sooo perfect for you, you have to see this, you will LOVE it!, are you free __ or ___ next week?" (be hyper intense and all excited, like it's the best thing in the world). When she asks what it is, just dodge the questions, "no don't want to ruin the surprise, gotta see it in person, too amazing to tell over the phone." Now shes sort of stuck, women can't stand not knowing what this amazing thing is and her imagination will run wild. She'll MAKE time to come out. If she says she can't, then you play it off like its no big deal, "yeah no worries, will save it for next time", but again you don't tell her. When she does come out, it can be something as minor as the most amazing restaurant ever.
I've used this a ton, no one ever complains over what it turns out to be, because by the time they come out, they are having a great time after a few drinks anyways. Very few women will turn down the invite, and the ones that do, find it eats away at them, until they ask YOU out in a week or two.
