What to wear?
Check the weather forecast and dress for the 10.30 - 11 am weather, not for 7.30 when you get out of bed! You'll soon warm up, and get uncomfortable sweating in long tights and a fleece. I reckon if it's 10ºC or less I'll need a beanie hat and gloves, possibly a long sleeved top. I might wear a small waist pack to stuff hat and gloves in towards the end of the race. If in doubt wear less!
Water and gels?
I always carry a small drink on a 10k, although I wont drink much. It gives the brain and legs an occasional boost to sip an energy drink, rather than having to wait for the drinks station. I use a small soft flask tucked under a wrist/sweat band so it's sitting in my hand without me having to grip it. Your body should have sufficient carbohydrate for a 10k, so you don't need to carry gels but you might like a boost from one 10 - 20 mins before the start. If you do, make sure you've tried this on training runs.
How to pace the race?
Plan a target time and work out your ideal pace. Divide the race into three sections in your mind. The first 3km run a few seconds per mile slower than your target pace. This helps get you into your rhythm and stops you hurtling off too fast and fading at the end. Dont be fooled by the first couple of kms being down hill, hold back even if you feel great! and reserve your energy for the rest of the course. In the middle 5km settle into your target pace, focus on your form. The course is undulating, so your pace wont be consistent. Stay steady up the hills and enjoy coasting down them. For the final 2km, push hard, dig deep, try to reel in a few people ahead of you. Remember, it will hurt!...focus on your breathing and form; think positive thoughts! and run as hard as you can to the finish.