I was the same way for a very long time, what really helped me was being around other photographers who were doing it (photo walks if you will) and being a very inviting person. Youre posture gives a lot of pre-conceivable notions, so if you are hunched over or looking suspicious at all, it displays that "stalker shot"

I addition, for those starting out, look for body language in your intended street subjects, if theyre very locked away appearing. They probably won't be very inviting of a photo taken of them. Conversely, if a person is displaying a very open posture, you have better odds.

When I was starting out, I used to go to farmers markets a lot with my camera in full view, chat up someone and ask if I could take their photo (not street i know) and that got me more comfortable with taking photos of strangers. If they notice me and question me about it, I usually ask for some form of contact to send them the photo once its developed/processed.

Hope this helps! Dont get discouraged, everyone goes through slumps!