Don't buy maternity pads. Get the biggest most absorbent posh Allways stylie shaped sanitary towels you can find. They are often on offer and feel a lot less like having a king size mattress in your pants.
If your DH says at 3 weeks "just remind me why we thought this was a good idea?" breathe deep and trust that your relationship will survive. You can't waste any energy stressing about that right now anyway!
Later, learn early on that banana never comes out of any clothes ever so don't even try.
Have your hair cut as short as you dare as close to the birth (before) as possible.
Giving birth with nicely painted toenails makes you feel glamorous and in control for the last time for months.
Arnica (Pillules) after the birth help with any (!) remaining pain, and lavender oil in the bath (twice a day) with help heal any stitches/tearing as it's a natural antiseptic. And the smell also serves as someone else said as a great reminder in years to come, of that lovely time...
If you have a home birth (especially if unplanned as you won't have thought of it) get DP to put the hot water on to max early in the proceedings! Leave it that way for weeks.
Be happy. There is (as Ines de la Fressange said) no perfect mother, but nobody is better than you for your child.