I'm no expert, but I'm losing weight myself at the moment for health reasons.
From my experiences so far, I'd share the following:
1) quick weight loss is temporary weight loss, slow and stead is the key
2) it's about lifestyle changes, not fad diets
3) be realistic - you can't go from no excercise to 2 hours in the gym 5 days a week - you might do it for a week, maybe two, but you'll wear yourself out. Start with just 30 mins exercise a day, then build up
4) eat a healthy balanced diet - not fad crap, just healthy. Lots of fruit, some nuts, some lowfat dairy, lots of veg, as little processed food as you can, and avoid sugar, fat, and salt.
I've found the DASH eating plan to be realistic, sensible, and effective. TBH - it's very common sense stuff. This PDF explains it well, and even gives some nice easy recipes to try:
http://anonym.to/?http://www.nhlbi.nih.gov/health/public/heart/hbp/dash/new_dash.pdf
DASH was designed as a preventative diet to avoid heart and blood pressure problems, and a way for people to get their blood pressure down, but a big part of keeping your heart healthy and your blood pressure right is having a healthy body weight, and that DASH eating plan helps with that too.
B.