My second basically lived in the Moby wrap, then my mei tai or the Beco while I chased my older dd around for about the first 4 months. I tried to keep going to playgroups, take her out on her bike, and take her to sports classes while I wore the baby. While he nursed I tried to read her book or engage her in some other activity. Preschool was such a life saver, so the fact that your dd will be in kinder is awesome!! You'll have great one-on-one time with the baby while she's in school and you can relax and do you stuff while the baby sleeps. I doubt there will be much homework in kinder so I wouldn't worry too much about that. Oh, and I have to say, just about all my rules about TV went out the window.
My dd LOVES her little brother. The hardest part about their relationship is how much she wants to interact with him... pick him up, carry him around, "play" with him, etc. when he was not really old enough for that (and she wasn't really strong enough either). Now that he's walking and playing more, their relationship is getting more and more fun. I have very rarely seen any jealousy (other than the taking away of toys she doesn't want him playing with). I can trust her to take him out in the (fenced) back yard and the play out there for long periods of time. It's great. She also likes to help with some aspects of his care. We've discussed a sibling bed with her and she seems very excited about that idea. We'll see if we actually do that or not, but it shows how much she likes to be with him. We of course still have some rough times with them where she knocks him down or retaliates when he swipes at her. I hear the book Siblings Without Rivalry is awesome, but I never found the time to read it!
With a 3 year spacing, dd was potty trained, STTN, and weaned so I didn't have double duty in any of those areas, which I think helps the transition to two be a little easier. Our biggest challenge has been meeting the needs of both kids, like when ds needs to nurse, but dd wants me to fix her a snack. Or when I need to put ds down for a nap and dd wants to go to the park. It's exhausting to use all of ds' nap time to play with dd. I need to take some of that time for myself. But I do try and carve out one-on-one time with her each day. We tried to maintain some of our previous routines, too, like dh and I both help put her into bed, read her a book, etc. while ds plays in the room with us.
I have to say though, that all the experimenting and all the knowledge and wisdom I gained from parenting dd for 3 years really served me well with #2. I was so much more confident in my decisions, which made everything less stressful. For example, breastfeeding initiation was easy and problem-free. I didn't worry about solid foods as much and confidently used the baby-led weaning technique. I knew so much more about babywearing and had several carriers on hand such that the baby was always happy in a carrier. I had my cloth diapering routine down pat. I didn't have expectations about sleep. Parenting the baby was actually a breeze and I think it really rubbed off on him, too. Parenting my older dd was the much greater challenge and really still is b/c her needs are always growing into uncharted territory for us as parents. So, my advice to best prepare for #2 is to actually further prepare for your older chid- thinking ahead to behavioral challenges, thinking ahead to school or classes that you can enroll them in, thinking ahead to friends and family that can assist you with child care, and building yourself a tool box of ideas to entertain and help make your older child feel special while you're tending to the needs of the baby.