I also find DD needs some quiet time in another room to wind down before a sleep when were out, only 5 minutes or so. A nappie change, a little game of peak-a-boo (the current favourite!), then I wrap her and bf her to sleep and pop her down.

I find if too many people are in her face I put her in the baby bjorn or in her pram in the corner and that will settle her, even if she doesn't sleep she can have a break.
Good luck!