When you come home (from outings/nursery etc), sort out DCs etc and then sort out the nappy bag (or similar) - replenish everything straight away so there are spare nappies and nappy sacks, wipes, tissues, snacks (raisins etc), spare clean clothes etc all in bag ready to just grab and go when you are going out again (just add fresh drinks and any fresh snacks needed) rather than needing to refill the entire bag when trying to go out.
Take some time when you have some peace to think through exactly what you would find useful in the bag (other than above - sunscreen, lip balm, nappy cream, snack packs raisins or other log life snacks, a book or small toy each, pad of paper and crayons, calpol sachets.....you might think of more or might not need as much). And make a list of travel sized things to get, 1 for the bag and 1 for spare (to quickly replenish as needed). Or find good travel bottles and label well, and either fill from your larger home bottles or buy larger bottles to easily refill (and cheaper in the long run).
Get plenty of wash and wear clothes, concentrate on keeping things washed and dried as needed but only fold and put away once a week (we fold while watching a movie here) - you can rummage for clean things in an emergency but it also takes pressure off needing to wash ans dry more frequently.