Disneyland with toddler

Hi! Next week we are going to Disneyland with my 2.5 year old. I hadn't planned on going until she's much older but I found out about kids under 3 being free and she's currently in the princess phase, so we're going!

I have never been (after living in Cali for almost 20 years). It will be just myself and my daughter, 3 day park hopper ticket. We're meeting some friends there, but won't be spending all of our time with them.

I've been reading lots of forms and talked to friends who have been there with young children but wanted to ask: please tell me the must DO and must AVOID things to do at both parks with a toddler (a patient and mature one but one who still takes afternoon naps).

Thanks!! ❤️