I'm not a doctor, or an expert, or even that good at this yet. But I would like to share a few tips and thoughts from my experience. You can read more about my "relationship" with running here, but long story short, I went from hating running to being a causual runner to enjoying running to becoming a half-marathoner. Hope this helps you break into the "sport" - I think everyone can become a runner if they want to.
Read Born to Run. It's a glamorized tale of running, for sure, but it's truly inspiring.
Start hydrating. Are you getting 80 oz of water a day? If not, start. Once you begin running more, water is even more necessary and drinking it doesn't get easier. Establish the habit early. Before the race, I was focusing on getting 100 oz a day. It's also important to make sure you have enough salt in your diet to keep your electrolytes up.
Focus on your form. I was lucky to have Paul as a "running coach" when I first switched to forefoot running. But you can check out youtube videos that talk about the same idea. I have been "forefoot running" since January 2011. The switch was hard on my calves, but I am now able to run easier and with less pain. There are minimalist shoes that are designed for forefoot running that will help you as well. I have been running in Nike Frees but am going to try New Balance Minimus now that the half is over. (I'll let you know what I think of them after a few good runs.) Keep in mind that it takes time to transition from standard running shoes to minimalist shoes. You may need to slow your pace and strengthen your foot and calf muscles before you can use the shoes safely.
Learn the difference between "real pain" and "being uncomfortable." Usually, over the course of a long run, a variety of different uncomfortable feelings pop up. Sometimes in my heel, sometimes in my knee, sometimes my back - whatever. I have found that refocusing on my form, adjusting my pace or stopping to stretch works them out. When you first start running, these minor aches and pains can make you feel like running is too difficult. You have to be willing to push through them. Obviously you may also encounter real injuries. Pain that doesn't stop, continues after you're done running or increases could be something more serious. Cut back and possibly check with your doctor for these!
Set goals. This could be signing up for a 5K or deciding to run 40 miles a month. Be sure your goal is measurable and work towards it.
Stretch at the beginning and end of every run.
Work weight training into your schedule. This is something I failed at when I first started running more seriously. I am now adding Bar Method to my routine to increase strength and muscle mass. Cardio shouldn't be your only form of exercise, especially if you are going for weight loss as you will end up burning off muscle in addition to fat.
Find a training plan. I loosly followed this one. I was running outdoors 3-4 days a week the two months leading up to the race and for me that turned out to be enough. If I do it again, I will focus on getting a few more long runs (8+ miles) in.
Tell people you're running a race. Your family, your friends, your facebook feed. Tell someone. Honestly, I don't know that I would have gone through with the half if I hadn't had made such a big deal about it here on the blog. I was that scared the days leading up to it. People knowing makes you more accountable.
Hold auditions for your race clothes. I have a few pairs of running shorts and a bunch of sports bras and running tees. All of them are different. When I was training, I paid attention to which shorts didn't irritate me, which shirt didn't ride up, which bra felt most supportive and even which pair of underwear were most comfortable for running. Then on race day I wore all "the best" stuff which kept me from fidgeting with my attire during the race. For the record, I wore these shorts, this tee, this bra (which I really like especially for the price), and this underwear.
Wear a sweatshirt or long sleeve shirt that you're willing to give away. It was chilly the morning of the race so most people were in long sleeves. As we got closer to the start time, people started pulling off their jackets and hanging them over the barricades lining the sides of the start. I was so confused - thinking maybe the jackets would be brought to the end of the race for pick up - but nope, all the jackets were given to the homeless. Very cool. Unfortunately, I had worn a relatively expensive pullover that I wasn't prepared to part with. I ended up wearing it around my waist from mile one on - super annoying and could have been avoided if I'd worn a different pullover (there is actually one in my Goodwill pile right now).
Drink at every water station. I made sure to down at least a cupful every time it was offered. Keep in mind the first few tables of water at each station are always jammed. Stay to the outside of the tables at first and cut across just before they end. You'll avoid the traffic jam.
Be prepared for porta-potties. I'm lucky that I never have to go the bathroom on runs. By the smell of the porta-potties, I am the only person who doesn't. Bathrooms are limited (some people waited in 20 minute lines) and get gross quick. If you can go before the race, GO.
Your Nike+ app might fail. I am just getting into using Nike+ and was very disappointed with how it worked on this race. It congratulated me on finishing 13.1 miles before I had even hit mile 12. Considering how rough the last three miles were, this was a blow to my motivation. I think I would listen to music again next time, but NOT have the false "mile updates" told to me.
Remember that YOU are your own motivator. I thought about this a lot on my run. I was pretty much alone with my thoughts for two hours and 15 minutes (plus the hour waiting to start) and all of that was spent focusing on the task at hand. The cheering section is nice. The signs are sweet. But every single step is taken by you alone. No one can motivate you to keep going the way you will need to motivate yourself. This goes for training too. Make peace with the person in your head; you'll spend a lot of time with them.
Remember that it is going to end. And at the end? You'll feel good. Sore, for sure, but good. And, yesterday? 24 hours post race? I felt AMAZING.
Hope that helps! As always, this is just my experience and what worked for me and my training. Likely everyone you talk to will have a different tale and your path will be unique as well. Good luck! And also, thank you so much for your encouragement these past few months and for the congrats yesterday. As mentioned above, this blog was a big part of why I was actually able to finish a half marathon.