i used to really worry about what other people were thinking too!
especially what others would think, if i were to walk up and open a set...
but after a bit of field work, i realised that if you just walk up and open with enough confidence, people would just assume that you already know the set, and think nothing of it!

if you still have problems, then take note of how you would approach friends, in terms of body language, and confidence... and just immitate this in the field.

it helped me, when i realised that other people, are too busy worrying about themselves to even notice, although critisize what you are doing

i hope this helps