Have a bag for labour with your stuff for that in (plus a pair of pants with a pad already stuck in) and a clean nightie/washbag in there too. A straw and lipbalm are handy to have in there, along with dextrose sweets or some snacks. Have one outfit for baby and a nappy in there too.
Then have your main bag with the rest of your hospital stuff in, and all the other baby stuff (extra clothes and nappies) which your birth partner can go and get for you from the car if you need to stay in - that way they're not rooting around a huge bag to find something you need in labour, and it's one less thing to take back to the car if you don't need to stay in!
In mine I've got:
Labour bag:
Pants and pad(s)
Lip balm
Flannel (for cold water)
A straw (can't hold the G&A, the MW or DH's arm AND a drink all at once, a straw makes it easier to drink in any position too)
T-shirt for birth
Clary sage and peppermint oil
Wash bag
Purple hand towel, main bath towel (pink and purple - don't take your fluffiest white one!) tucked through handle
Nightie
Nappy, babygro, vest and one blanket
(need to get dextrose sweets and some cereal bars, throw in phone and charger at the last minute)
This sounds like a lot - but it all fits into a small bag apart from the large bath towel which fits in the handle.
Main Bag
Maternity pads
Lots of knickers (cheap black Primark ones, full briefs in a bigger than normal size - not disposable ones for me)
A few babygros, vests, nappies and wipes
Flip Flops
Change of clothes
Nightie and pyjamas (I'm a jim jams girl even after birth)
Nursing bra
I don't take breast pads, milk doesn't come in until day 3 so chances are you won't need them until then, and I have no intention of staying in that long - I was in long enough with DD thank you very much (36 hours post birth) 