Aggressive baby?

My 10 1/2 mo babygirl has the habit of hitting... she kinda slaps me, my husband and the other babies at daycare.

The pediatrician suggested we don’t make a big deal out of it, and not to show emotion and also to hold her hands and say “we don’t hit” or “no hitting” but that’s not working much.. She did get better for a while but started hitting again. I speak very firmly with her and look her in the eye while speaking to her.

I’m afraid she’ll get worse at daycare and hurt one of the other babies.. she’s strong and kinda big for her age.. any suggestions?