Start with the obvious items (it's called a diaper bag for a reason!). Diapers - enough to get you through the whole day, even if you're only going out for an hour or two. Wipes - a full package. You can never be too prepared with wipes. Soothing item - pacifier, blanket, stuffy - whatever your child needs to soothe.
Depending on the age of your child, add bottles, a nursing cover, puree pouches, crackers, or health bars to hold them over for a few hours. If you're packing for a newborn and are bottle feeding, be sure to pack extra formula and a spare bottle in case you're out longer than expected. Running out a food for a newborn is not a fun experience for anyone!
Don't forget to pack a snack for yourself. Even a small cereal bar or an apple will suffice if you're starving!
Throw in a teething toy or rings for a child under 9 months. For children ages 1-3 the options expand. A coloring book with crayons is always popular. A slim book or a busy wallet work great too! Magazine or tablet for yourself.
Spring/Summer - sunscreen and more sunscreen! Add and hat and swimsuit (plus swim diapers!) and you're all set. Fall/Winter - tissues for the running noses, and an umbrella.
Now that your kids a fully packed don't forget to pack your essentials. Wallet, cell phone, keys, chap-stick or lip gloss, and anything else needed to get through the day. Espresso shot? :)
Want to take your organization to the next level? Throw in an organizer like ToteSavvy. You can even toss this sweet insert into a regular tote bag, turning it into a fully functional diaper bag.