I can't guarantee this works for everyone, but it has worked exceedingly well for me. If you really want this you have to work for it. 'it' being a relationship with a woman which includes tickle & foot faggotry. A normal relationship takes a shitton of work by itself. This takes more. If you want both you have to work extra hard for it, there's no way around that. Otherwise have fun dealing with the fucking nutjobs who do tickle stuff without relationships. With that in mind, never call it a fetish or a kink. Establish the relationship, be a giver in bed where possible (but not so much that you're a pushover pussy because she'll either get tired of you or will take advantage and never feel she has to reciprocate). Try to steer the sex life towards experimentation, but in a very subtle innocent sort of way, asking if there's anything she's ever wanted to try. Don't come out and be like hey what's your fetish or crazy ass kinky thing you want to do. If she has something like that, you need to coax it out gently. The whole idea of this is that you get her to break the ice on kinkiness, and ideally you'll get to indulge in something she likes so that she'll be pliable to do the same in return. And here's the clincher - when you already have a physical intimate relationship established and she's attracted to you that way, introducing an activity such as tickling which puts the cock she loves into hyperdrive will be such an easy sell.
Shorter version. Get a relationship first, get her attracted to you being aroused, give her a means to make you diamond hard. Don't ever call it a foot fetish or tickle fetish. It's just the thing you like. It's worked for me.
Sidenote: those uggo chicks make some of the best ticklers if you ever want to swing that way. Tap into that crazy tickler horniness they have from being deprived.