How to prepare for marathon?

There are a lot of variables. Like, How long have you been running or are you just starting out? How many miles do you run a week now? You really can't just push yourself "harder every day" you'll injure something! (ask me how I know!) You can only increase by about 10 percent each week. for instance last week if I ran 19 total miles I only want to go up to about 21 miles this week. then the next week I will go for 22-23 miles and so forth. There are a lot of plans on runnersworld.com I usually take one of their training programs and tweek it to fit me! You might try that!

Since there are so many free training programs online, I'd advise you to look at a few. You don't have to run daily, but I would recommend that you do at least 3 days a week. Remember that rest is also important, so you may not want to run each day. It's not really pushing yourself harder each day, it's more of building endurance each week. One long run each week that gets longer every week until you get to at least 20 miles for most plans. And then speedwork, tempo runs, and easy runs will vary based on what program you have. And if you want to do a hilly marathon, you'll need to do some hill training as well. A healthy diet would probably help too. Good luck! I'm running my first marathon next week. I followed a 16 week plan.