Hi there,
I have a 2 year old dd who has recently gone through a 'drive me crazy' phase too. Here's what I experienced / found helped.
Personally, I found getting out in the morning a nightmare battle! Everything from getting dressed, to brushing teeth, getting shoes on, coming down stairs etc etc was a total battle.
Getting dressed: now I make sure I do it before breakfast as mainly it means DH is around to offer a bit of support - often it's enough for him to take her to one side and talk to her. I think this calms her down and stops me from getting 'cross' so a win win there.
As for battling with teeth / shoes etc etc DH said to try asking her 'what do we need to do next?'. I tried this twice: once it worked - she told me and co-operated, but then on the second use she told me, but said 'in a minute' which isn't very helpful when you're in a rush.
What I found really useful is to do all of above in one swoop. I.e. once I have her co-operation to do teeth I no longer go off and do something else, but focus on getting her completely ready and only then do whatever else I need to do.
Just before heading out, she would often say 'not want go group' for example. DH has said to say ok etc and then she would change her mind and again I used this once and it worked. The I say black, she says white scenario I guess.
Re the shouting / crying. After the obvious reasoning with her, I would then try either ' go in the other room if you want to cry' and she would either stop or go in the other room and cry for a minute before finding something more interesting to do. Or I would say, 'do you want to go to bed' and with her response of 'no' I would say well stop crying then and after a couple of seconds reinforcing this statement she would stop. I don't like using this latter one though cos I don't want her to associate sleep with a negative connotation, but I have used it out of desperation occasionally.
Do you find that you anticipate her tantrums which puts you on edge before anything has happened? I was and think this negativity was coming across a bit. It's hard, but I tried to go into things more optimistic and with a smile on my face which I do think helped when I managed it.
My DS is too dropping her daytime nap but not really coping with it. She used to nap for 2 hours every day, but now only has one more like every other day i.e. tiring herself out one day and making up for it the next. Someone suggested to try waking her after one hour in the hope she will sleep for one hour every day, but I haven't tried this as think it's a bit risky, but it might be something you would like to try?
Luckily this phase is pretty much gone- or easier to manage (not sure), but I'm under no illusion that she will try me again soon - especially as I have baby number 2 joining us soon! I hope some of what I've shared helps. Good luck.