I wear my collar 24/7 as well. It does help. But, even then there are times when I will forget myself. My Master and I were best friends for many years before we entered into a D/s relationship. I slip back into that on occasion, and will often get myself into trouble. *grins* I'm fantastic at getting into trouble...

I would suggest something more than just a collar. Perhaps wristcuffs, or an anklet with small slave bells. Then you can hear them jingle as you walk around. The sound might help get you into the mindset you're looking for.

I find for me, when I'm feeling off, or not in the right frame of mind, I'll sit at my Master's feet for a while, and rest my head on Him. Usually He'll pet me and that will help me slip back into where I want to be.

Good luck, I know you will find something that works for you!