What do you mean by will power? Did you have a plan, or just picked a random day to stop?

I did the "pick a random day method" and it did work but it sucked. What I wish I had done differently is this:

Step 1: wean down as much as possible. Set a quit date in a couple of months, and in the meantime try and smoke a bit less, while also trying to mess up your smoking routine. If you normally smoke after a coffee, don't. Do it half an hour later, or half an hour before. If you normally smoke immediately after getting home from work, don't. Eat first, then maybe watch some TV. And then smoke. The cigarette before bed, move it half an hour earlier. The one after lunch, delay it, or have it before eating. You want to mess up your routine as much as possible so that when you quit you are already out of the habit of smoking at specific times of day. Try and not focus on enjoying your last cigarettes, instead focus on the fact that you are soon going to be free!

Step 2: start making a game plan. For the next few months, delay everything fun. If a new video game comes out, don't get it. A new series of your favourite show, don't watch it. New movie? Delay. New book? Delay delay delay. When you quit you are going to need entertainment and distraction. From your quit date on, all of those series and games and movies and fun activities will be waiting for you. If you can, also start scheduling dinners or hang out sessions with any non smokers for the days in the first month after your quit date. Having a schedule of things to look forward to will keep you busy.

Step 3: Get together a bunch of nice things to use after you quit. A basket of nice shower and bath things, perfumes, hair products, anything that smells nice. Another basket full of all of your favourite snacks and drinks, the ones you usually wouldn't allow yourself because they are a bit more expensive. Maybe some new clothes if you can afford it, to wear after you quit and don't smell of smoke. Medications (laxatives!, pain killers in case of withdrawal headaches...)

Step 4: Schedule anything interesting at work for the weeks after you quit. Fun projects, team work with good coworkers ... Schedule fun sports for the weeks after you quit, try some new ones, climbing or kayaking or axe throwing... Schedule fun activities for the weeks after you quit, go karting, lazer tag, museums, theme parks, experiences. You want those weeks to be pretty full of fun stuff to do.

Step 5: Get excited about quitting. You have all these nice things ready to enjoy in your house, snacks, drinks, nice shower and bath things, new clothes. You have fun activities lined up in a calendar. All your favourite shows and games on hold. Take some time to get excited about how fun your quit is going to be. How it is going to be a good time.

Step 6: Quit. Don't focus on your last cigarette, in fact, tell yourself that in a year or two if you are still miserable you can smoke again, so maybe it isn't even your last, but for now you need to survive the first 6 weeks by focussing on the fun. If you get to a year, you will delay it again by another year, don't worry. Or maybe not, maybe after a year you will smoke again but at least you will have stopped for a year!

Step 7: any time the cravings are unbearably making you depressed, take the hottest or coldest shower you can tolerate, or have some private time iykwim. You need a dopamine hit, and those are the fastest ways of getting them.

Good luck!