I go to bars with friends if I don't know the place...
If I have already been there I don't go with friends at all, I tell the girls I'll be there, and I tell the guys I'll b there. I don't care if any of them show up, they are not there for entertainment, nor to give me social proof. You have to prove social proof.
Once I've been in a place I sarge for new friends, make comments to random people the first time around, next time in there I scout for somebody I talked to the time before, and while I am with them I scout for tables with hot girls, group tables are best where people aren't hangin out together... Than I expand and jump on a few conversations and see if I can take control, steal a seat and BANG new friends.
It doesn't matter if you go alone or with a group, you create your mindset and start picking people out that seem interesting and using their energy if you have none of your own.
Friends can be cold approached as well, you get spankin new stories from every new person you talk to, there are some that won't welcome new experiences, and those are the people you avoid.