Most of my close friends are women, and we were friends before I started to transition. It's cliche to say "just be yourself," but that's what worked for me. Granted, I'm in a wheelchair, which has two effects: 1) practically nobody will look at me as a sexual being, 2) I never show overt sexual interest in anyone because the odds of rejection are near 100%. Now, you probably won't have it as easy as me if you can walk, but if you can remove or minimize the presence of sexual tension, friendship should be easy. Find women who share in an interest, take part in that interest with them, and build from there.