I was quite philosophical, I had to be, as DH worked away and we were living with no support networks each time a baby was born, so knowing that and there being one of me, if I had to tend to the baby, that's what I needed to do and I tried to implement some routine into our day. I would always reinforce that there was only 'one Mummy' so sometimes things would have to wait especially in the early days when I perma-feeding etc. I found that the toddler(s) would try and gain my attention by doing mischievous things, especially when I was preoccupied with the baby such as breastfeeding or bathing etc and I ended up buying a sling/wrap etc to have the baby in so that I had two free hands most of the time. I would also have an 'activity box' for the toddler to go through which had colouring in, toys, books etc in it. I always tried to read to the toddler whilst I was feeding. I also used to make up 'platters' and put them in the fridge on bottom shelf, so that we always had healthy snacks at the ready.
Things I also found helped me, were having DH give lots of time and attention to the toddler as soon as he was home from work and that helped a lot and then giving him the baby so I in turn could give lots of attention. I was also super firm about rules for when we were out and about, such as 'always hold Mummy's hand' , 'hold the pram', the 'shopping trolley' etc, because if there were ever a time the toddler would run off or hide, would be when out and about at the shops or something. Gah, this is bringing back memories of super busy times lol but I don't think I have ever been more organised then I was when I had a newborn and toddler, so to that end, it helped me ward off pnd and loneliness as I had so much to do and factor into my day etc.