This worked well for a friend on an old weight-loss community, so I'll give it a try. Rather than trying to change all of my habits at once, you change one habit at a time, and after you've been working at it for a week, you add the next habit to change into a cumulative effect that, in theory, is a lot easier to get into. Kind of like when smokers quit by having one less smoke a day one week at a time. One less habit at a time.

So here is a breakdown of the bad dietary and lifestyle habits I need to break, week-by-week:

Oct 1-7: I need to sharply limit what I am going to buy when I eat out, especially at the cafeteria at work. Salads of various natures are okay, pre-made meals can be guestimated (for now), and diet pop/low-sugar juice/water to drink. I guess sushi is okay too, but I don't like sushi. The freshly made burgers, pizza, fries, and onion rings are NOT OKAY. Neither are the several kinds of pastries or the ice cream bin. Unfortunately, these products make up about 75% of the cafeteria's output. Thankfully, this week starts hour-long lunch breaks, which means that if I must buy a lunch, I can go to the nearby shopping center and get something marginally wholesome. Sub places, pita joints, and even regular fast-food all over the place. Hell, I could even go to the Superstore and pick up actual produce if I wanted. I have NO EXCUSE to at least make a significant improvement in the quality of my food intake.

Coming up:
Oct 8-14: Cut out the not-water beverages and replace them with yes-water. This may be difficult considering a significant caffeine addiction. I need to kick that anyways.
Oct 15-21: Get stricter with my food intake and start monitoring for specific nutrient levels (carbs, protein, fat, fibre)
Oct 22-28: Make significant effort to take multivitamins and supplements EVERY DAY.
Oct 29: Reflect upon improvement and make a new plan for November.

Note:
This past week I worked on doing my workouts without my husband having to nag me four times to do it. He still did have to nag me one night, but four I did entirely on my own. Getting started as soon as I get home from work is much easier than taking half an hour to sit down, relax, chat about my day and generally getting lethargic and then trying to get the energy up to bounce around. My workouts have generally been of better quality because of this too.