L.L.
My daughter is also 2 1/2. She tells my husband and I most of the time but won't tell daycare but will go when they tell her. They think it has to do with too many distractions to think about going to the potty. So we haven't perfected it yet either but here are some ideas and i will watch the responses to get some more ideas that might work when other people watch her.
I try not to bribe but this worked for potty training for us.I told her, "This is the piece of candy you get when you tell me you have to go potty" I think you need the reward visible while she's playing so she remembers about it at first. Different things motivate different kids - a sticker, a fruit loop, candy. Just reward for telling you even if she doesn't quite make it to the toilet. Lots of verbal praise when she tells you.
My husband and I make big announcements when we have to go potty and then we play run off to the bathroom. I guess it's modelling the behavior for her. We just have to remember to keep it down when we have company. They give you strange looks when you make such announcements.
I put her straight into panties and just cleaned up some messes. So she knows when she has gone and she didn't like the idea of a big mess of the floor and her clothes. So that also motivated her to tell me. I didn't rush her in on a regular schedule. I allowed her to have a few accidents that I just casually cleaned up. So she got used to the feeling of really having to go. (Plus personally I couldn't keep up with regularly scheduled bathroom trips)
When she tells me she has to go I make an exaggerated game of racing her to the bathroom. (At first it made her laugh too much and she peed on the floor in front of the toilet) It's still fun to race but not hysterical anymore so it works for us. She feels the need to go and gets excited about the racing to the bathroom game.
Sorry I ramble. Like I said we are still a work in progress ourselves. Hope something from here helps. Good luck! Have fun with it. I try to laugh when I want to pull my hair out it saves on the hair dresser bills. And remember as a friend told me just today, all the college kids are potty trained.