1. Quit drinking your calories (especially alcohol)! Just look at the number of calories you consume in your beverages. If you're on a 1500 - 1800 calorie per day diet, and you drink 500 calories per day, that doesn't leave much for the food.
2. Don't keep high calorie snacks in the house (i.e. no big bags of potato chips "hiding" in the pantry). Make it so that if you want high calorie snacks, you either have to make them yourself (i.e. bake the cookies from scratch) or walk or cycle (not drive) to the grocery store to get them. I lived without a car for almost 6 years. My grocery store was a 2 km round trip walk. I did the trip about 3 times a week to buy "essential" groceries, which also included food and supplies for my cats. If I couldn't carry the groceries 1 km home, I didn't buy them. Therefore, I had to make the decision in the grocery store whether I wanted the snack food or whether I wanted something I could have for dinner. And if I wanted the snack foods, I had to walk to get them. Made a big difference in my calorie consumption, and my weight.
3. Exercise consistently. "They" recommend exercising 60 minutes a day (420 minutes or 7 hours a week) to maintain your weight, and 90 minutes a day (630 minutes or 10.5 hours per week) to lose weight. So do that. Consistently, every week, aim to get at least 10.5 hours of exercise. It could be an hour on the trainer 6 evenings a week, plus 30 minutes of walking at lunch 5 days a week, and 30 minutes lifting weights 5 evenings a week. Or maybe 1.5 hours in spinning class twice a week plus an hour on spinning class night jogging around the track and doing some light weights, plus an hour on the trainer 3 nights, plus a 30 minute walk at lunch 5 days a week .... or whatever works for you.
4. Mix it up a bit ... include some other sports (snowshoeing or skiing), try a different type of cycling (snowbiking) ... add some different things into the mix to keep it interesting over the winter.
5. Pick several goals ... or a year long goal. One of the things I like about Randonneuring is that you can work your way up ... complete the 200 km, complete the 300 km, complete the 400 km, complete the 600 km (get award), complete the 1000 km or 1200 km ... etc. That's one type of challenge that keeps leading you on to the next and the next so that you're not just going for one thing. Another idea that has often worked for me is the Century-A-Month ... ride a century (100 miles in one day) each month of the year throughout the entire year. Every time I think about slacking off, I know that the century next month will be harder if I do, but will be easier if I keep exercising consistently now. You might have a browse through the Long Distance forum to get some ideas.