1. More than 2-3 hours on an early date? Never again. Long "productions" of dates early before you get the lay of the land as to whether she is a waste of time? Never again. Flirty buildup before early dates that make you think you are in? Never again. YOU are getting heated up. SHE is sopping up the FREE ATTENTION that she doesn't have to reciprocate other than throwing you a few "jiggling ass" crumbs, formulating all kinds of hamster wheel as to why she shouldn't sleep with a guy she works with and formulating a shield... in this case ex talk. Do all your flirting and seduction on the 2-3 hour date. Silence is the best anticipation on early dates.
2. Sitting, smoking, drinking and talking on early dates... especially across a table? Never again. Get them moving, doing something active. Anything, walking near a lake, window shopping, bowling, anything other than sitting. During break times when you sit, make sure they are sitting next to you at a bar, preferably a moderately full but not too loud bar where people are having a good time around you, never a silent place with a couple of sad sacks hanging around.
3. If you go into a bedroom with a woman, you will be having sex with her within 15-20 minutes max or you will be politely leaving, withdrawing attention, showing no negative vibe or pouting whatsoever. Never again place yourself in a position to get stuck in this way. Initiate, initiate, initiate, until it's plain it isn't happen and then withdraw, making it clear the tease game isn't going to get her more attention. This will very often result in a pullback and give-in once it becomes apparent you aren't going to play tampon.
4. Allowing the conversation to go into ex talk? Never again. You always have something better to talk about that you can sell to her as being better to talk about. Every second of ex talk, or any talk you are letting her run with allows her to associate you emotionally with feelings you have no control over, could be sexy or good, could be regret or remorse, don't flip that coin.
Enough for now, but I suspect you learned all this stuff through this experience. See there, it wasn't a loss after all, you are improving, and will continue to improve until early dates do not resemble what you had with this one (from WORK... which almost makes it a good thing more didn't happen) in any way. Good luck.