In a dating situation some behaviours to avoid rejection are:
* Staying centred - Don't appear too 'needy' or 'clingy'
* Being respectful in attitude and in your actions towards the other person. Including the language you use in your discussions.
* Don't be physically forward (don't grope!)
* Don't discuss emotional baggage/issues too soon.
* Don't call or message the other person every 10 seconds!
You can only be true to yourself - you might be the most perfect, beautiful creature in the whole world, yet you still can't totally avoid rejection from time to time. In that case, remember it's not you, it's the other persons loss.