Go slow at first, but then go faster/harder once she's relaxed. If you just keep going slow most women think it feels like pooping (from what I've been told.) I've heard about women who like slower but never met any.

Something you might try is the direction of your thrust. Try thrusting very slightly more downwards (towards her stomach) or upwards (towards her spine). Women usually either prefer it one way or the other, and a woman can go from hating anal to loving it pretty fast if you aim correctly.

Also generally deeper is much better. Most women enjoy it deeper in my experience. As deep as you can go. Harder thrusts as opposed to more frequent thrusts tend to be better.

And use your hands to stimulate other parts of her. Lots of spanking, grab her by the hair, play with her boobs, clit etc.

I find the best positions are prone, doggy and on her back. Women will usually prefer one or more. Spooning makes it really difficult to thrust properly I find, too much friction with whatever you're on. Girl on top is specifically hard for me so I can't comment on it much, I need lots of stimulation to keep my dick hard and I find most women don't have energy or aren't strong enough to move up and down very much.

As lube goes, use water based if you're using condoms. Silicon based is the absolute best because it doesn't wear out and doesn't get sticky like water based lubes can. However silicon based lube is VERY difficult to get off of things and hard to clean up. Coconut oil can also work but usually isn't as good as water based lubes and is a bit more messy I find. In general I stick to water based lubes, but if you and the girl are alright with dealing with silicon lube after and you don't need a condom - silicon is the best.