Foreword: I've no professional running or coaching skills, this is merely experience.
Set yourself a distance that means your completely tired by the end, and try and complete it at a constant pace depending on if you want to improve speed or distance. For distance I usually just run as far as possible while breathing at a rate I can still talk at, and gradually increase the distance over time, keeping at my limits of distance as they improve. For training your speed, do the same thing, just increase the pace at which you run to keep at your limits. I usually just aim for a slightly higher min/mile each time I run a regular route.
If your non-professional it's not going to matter about hitting that exact sweet spot of off time and muscle repair. Just run often enough that you ache the day after and it was difficult but make sure you take a break. I try and stick to day off, day on, day off, day on, but not too worried if I miss one due to busy weekend / work day. Just pick it up again as soon as possible, and don't try and push hard to "make up for it" it usually ends in you missing more runs through injury.
Enjoy it. If your not enjoying it your going to be wanting to give up. Run too often and your going to be hurting too much, not enjoyable. Run too little and you won't be improving, not enjoyable. Vary the places you run wherever possible, though I like to keep some regular routes as a measurement of my progress. If your not enjoying it, the only thing keeping you going out again is a desire to reach your goal.
Set your goals. Even if it's just a short term, run at
x pace for
y miles or a long term , "Run a marathon in 12 months" you're going to need something to head towards. So when it's snowing, freezing, you ache, have lots to do, and it becomes difficult to enjoy you'll be able to push through chasing your goals.
Also depending on your disposition, recording your runs via GPS and keeping a long term log can be a big motivator. It can also be a de-motivator if you don't get along with technology or data logging though :)
You will be generally fitter after this, it's almost impossible not to be. And yes you may actually put weight on (depending on your build and how muscular you are now). But it will be entirely different weight, you will put weight on by building muscle in your legs, but will be burning fat from all over your body. So I wouldn't worry about it, aim for fitness not absolute weight loss, and you will generally come out much lighter if your on the big side now.
Of course, if you want to train professionally then most of that is probably bull.