How do you manage sales people / promoters who flag you down, especially when you are not interested to talk?

I know we can smile and tell them "not interested" or "thank you", or maybe put on earphones. In shopping malls, I can walk another path, but when they are at the entrance of LRT/MRT, there's no way to avoid. Lately I find that even with earphones, they will stand in front of me and wave at me to get my attention. This happened at different locations in the Klang Valley. So, just want to ask how do you all manage and if there's any other respectful way to turn them down without talking.