There is nothing life changing here. Just five very simple things that I found made my days easier.
1. Keep a small package of diapers as well as a pack of wipes in all vehicles you drive. Always. (Trust me - when you are changing your baby's diaper in the back of your car only to discover that you have no wipes in your bag - oops - you will be glad you stuck that container of wipes in there.)
2. Keep one extra outfit for baby and an extra shirt for you in all vehicles you drive. (See above.)
3. Non latex gloves. You can get them in bulk at Costco. Seriously. You deal with enough gross stuff as a mom, when your kid has a poop explosion, or Poocopalypse as I just saw Noah Rothman tweet, it is nice to not get poop all over your hands. (And just so you know, regardless, you will at some point end up with poop all over your hands.)
4. Buy a baby carrier. Personally, I love the Baby Bjorn active mesh carrier. The mesh part is key for airflow. For the first year of my son's life I used my Baby Bjorn so much more than an actual stroller. It is so quick and easy to strap this on and pop the little guy in it when shopping, walking, running a quick errand, etc. As he gets older the stroller is a better fit, and I am sad that he is just a few pounds away from being too big for his baby carrier. They are not cheap - but it is so worth it.
5. Write things down. I do not mean about baby, although that is a good idea too. I find I am always thinking of something I need to get or do, but then I forget. Baby Brain is real. I think. Anyway, I keep a notepad on the island in our kitchen where I am constantly jotting stuff down (anything - lists, passwords, phone numbers) so I do not forget. It helps me stay organized and gets rid of a great deal of unnecessary stress.