When I gave up smoking I did it by going cold turkey - can be hard I know but here are some tips that worked for me.
1. Take 5htp (you can get it from Health food shops - I got mine from Holland and Barrett). It raises your seratonin levels so helps you to sleep and keep happy.
2. Eat what you like - treat yourself - worry about weight issues later.
3. Take more excercise (doesn't have to be the gym - I go for brisk walks)
4. Drink lots of water or herbal/decaf tea.

Hope this helps - the 5htp works wonders for me.