How to get my mileage up safely over the course of the next 3 months

I love to go running, it's an awesome activity to do in my free time. I've only been running for about 4 months now (I can't run in the winter because it gets cold here in Chicago) and I'm capable of running a 10K nonstop in about 52 minutes and I'm also trying to increase that to a HM. I don't know if this plan will work for you but I run 3 miles on Monday, rest on Tuesdays (rest days are important) Wednesday I do cross training such as weight lifting, or biking and swimming in the summer, Thursdays I run 3 miles again however with every week I increase it, for 8 weeks because that's how long I'm training for this HM. Fridays is rest, Saturdays is interval training and Sunday is kind of like a rest run, just a 30-45 minute run at a comfortable easy pace. So basically it's the same every week except I increase my miles on Thursday and try to beat my interval training lap times on Saturday. Hope this helps you!

You need to do things to strengthen your core, planks, crunches, squats, pushups, etc. and also maybe get a brace to help support your knee. As far as increasing mileage, only add about 10% a week to your long run. Check out Hal Higdon online, he has some great training plans for half marathon newbies. I would suggest making your longest long run about 12 miles, and run at least 10-12 miles at least twice prior to the end of March. A sample week I'd do would be Sun- long run or rest (7-8 miles), Monday- 3-4 miles, Tues- rest or cross train (core) Wed- 4-5 miles, Thurs- rest or cross train (core), Fri- 5 miles, Sat- long run if you didn't do it on Sunday (7-8 miles). The following week keep the same schedule or mileage but add one mile to Sat or Sun. Try to go for a minimum of 17-20 miles a week total. Question - how fast are you running? Don't train at your expected or desired race pace, especially on long runs run about a minute and a half per mile slower. I ran my first half in 2011 and although I had an excellent time, I do not recommend doing what I did . I had no clue about fueling so I did not wear a fuel belt or carry any energy supplements like gels or clif blocks. My longest run prior to the half was a 10 miler on my treadmill. I ran the same half last year and PR'd by 11 minutes, I'm shooting for another PR this year. I've trained a lot more/better in the last year though, between doing relays and other halfs and a marathon. Just remember, first and foremost is time on your feet. If you don't go out and run about 12 miles, go out and run for 2 hours. The last part of the race will feel tough if you are not used to pushing through it at the end.