This is SO EASY, you can start doing it RIGHT NOW without any practice.
1. Don't make unsolicited comments about women's bodies.
It's not a compliment. It's annoying at best (if we're beautiful, we KNOW we are beautiful — it's basically like saying the exact same thing everyone else we've ever met has already said and expecting a pat on the head for it), and creepy and inappropriate at worst (at work, at the gym).
If you want to compliment something, it should not be her body or appearance. It should perhaps be something she actually cares about and worked to achieve. Perhaps something that indicates you care about her mind and not just her body.
2. Keep your hands to yourself.
It is REALLY not that hard. Do the thing your teacher taught you in preschool: keep your hands to yourself.
There is nothing creepier than someone I barely know touching me — even and especially in non-sexual ways.
3. Stay out of other people's personal space.
No one likes it when you stand too close, sit too close, etc.