...and another thing(s)...

Don't over-train: consider putting hard-ish runs in, but every other day. This gives your body time to repair.
Don't run in knackered shoes, make sure you shoes are right for your style of running. A decent running shop won't sell you unsuitable shoes, they'll get you to run up and down the pavement outside the shop whilst they watch your gait.
Don't forget vaseline: runner's nipple / groin can be very sore.
Don't go out on the beer (even for just the one) the night before a race...you won't believe how much you'll dehydrate.
Don't forget a bit of loo paper.
Don't forget safety pins for your race number.
Don't forget to smile when you run....it's fun really!

Do listen to the advice of experienced runners, although try to be selective....not all advice is relevant to you.
Do try a couple of 10k races, they'll give you an idea of what goes on and they're good training too.
Do try to time your training runs to coincide with the time of day of the race.
Do drink plenty, consider 'electrolyte' drinks, or a much cheaper alternative: dilute some decent cordial (I use Rock's Organic Orange or Lemon) and add a pinch of salt.
Do rest plenty, but keep moving in the few days leading up to the race.
Do enjoy your day, I'm a seriously crap runner but I REALLY enjoy myself.

Very best wishes for your run,

John