It wasn't as bad as I was expecting, manzanilla. In answer to your question, I find it easiest to put on my work hat and assume the nursery will phone me if they need to. That way, work seems quite normal really. I think it helps that I love my job, so when I'm back at work I really enjoy my day. (Am I allowed to say that?!) Do you like your job?
The only parts of the day that are really rubbish are the transition times between work/home and home/work. Dropping her off in the morning is difficult - not the actual dropping off, because she's quite settled at nursery now and likes the staff there, but walking to the station once she's gone feels horrible. I don't like that bit and get a bit sniffly, to be honest. Once I'm on the train I'm fine though.
Then coming home I'm usually all excited to think I'm going to see her (which is really really nice!), but if the train is delayed and DH texts me to say she's fallen asleep or is going to bed, then I feel terrible. As it turns out, there hasn't been a night yet when I haven't seen her, but I can imagine it will happen at some point.
Did you stay with your DD for the whole trial session? She might find it easier without you there, or at least you could try it to see how she gets on. The other day my DD was all happy and playing, and I was about to leave, but then I had to go back to speak to the key worker about something and as soon as DD heard my voice she burst into tears. I think they are ok until they realise you've been away.
As far as tips go, I only have one: organise, organise, organise! There is NO time for things not to be ready when you need them to be, so you have to make sure DD's clothes (and spare clothes - God they get through loads at nursery!) are ready for the morning, and any other random items the nursery asks for (spare wipes, comfort objects etc). I have notes on my fridge, kettle and the toilet cistern (!) of things I MUST NOT FORGET!
It could just be me, but I find my memory isn't what it was pre-baby, and I just wouldn't have time to go back to the house before work if I had forgotten anything.
Hope this helps!