In the morning as we're getting ready for the day, I wear a baby and help the older kids get breakfast, dressed, teeth brushed, etc.
Throughout the day I give the baby floor time, or in a pack & play, swing, bouncer, crib -- not for extended periods of time. Just long enough to handle the other kids' needs, and then come back to the baby. It is ok for the baby to fuss a bit during this time.
99% of the time I am on my own at bedtime, so I bring the baby into the bathroom with us while I bathe the older kids. Baby sits in a bouncy chair. After bath I move the bouncy to the kids' rooms and he sits there while I help the kids dress and read, or sing. Usually I am feeding the baby a bottle at this point, so if I am reading and don't have a hand available, I just prop the bottle up for him.
I usually wear my baby when I cook. I have a Sleepy Wrap (identical to the Moby) so he is tucked away happily as I am cooking. My babies also like motion, so I kinda dance around the kitchen while cooking to help keep him content.
Yes, I do feel like each of my kids gets a little less attention from me than the one before them, but they also get attention from their siblings. When my oldest was a baby he had 4 adults in our house and was hardly ever put down. My in-laws moved 1500 miles away before my 2nd was born. My 2nd child is more independent than our 1st, and my 3rd we refer to as our "crown jewel" because he just is so ahead of the pace of his older brothers.
I've never been able to nurse, but certainly have had the crawling toddler while I'm giving the baby a bottle. It works well for us to use that time to read books, sing songs, or work on puzzles. I pull an ottoman up near the sofa and my older kid can work on the puzzle with me to help him when he gets too frustrated, so he still feels like he's being interacted with. You could even (insert gasp) watch tv with your older kid while you're nursing. Sure, you might not really be that into "Team Umizoomi," but if you watch it with him with enthusiasm he'll probably give you a nice nursing experience.