Street photography is never sneaky. In fact the more sneaky you are the more conspicuous you will be. Relax, let people know you are taking picture and avoid jerky movement. Smile alot, chat with strangers if possible to put them at ease. Capa used to say that let people know that you like them and you could get 'close' to them. Always respect others rights and if they do not like to have photos taken, give a smile and a short bow and walk away. Always be prepared to talk your way out. I was confronted once when I was taking photos of some Baskers. One of them turned aggressive and demanded to have the negatives, I have to calmly talk to him for more than 15 minutes to reassure him that I am not press and I am just documenting Singapore street culture and no images of him will be used for commercial purposes. You could take a look at my PBase gallery, all the street and documentary work is done with a 35mm prime.
1. mount a lens < 50mm so you have to get real close
2. engage the subjects
3. make your intention visible (do not hide camera or behind tree)
4. respect subject's decisions if they object shooting
5. act weird (slap youself on the head and scream "I will not obey you") when confronted