Right now, I wouldn't generally suggest focusing on getting yourself into in-season shape. You want to peak your body in February, not in September.
With that said, you still want to work out, just not 100% season practice intensity. I would suggest starting to build your aerobic base and running a minimum of three days a week (if you aren't already), and probably a maximum of five days a week. At first, just run around three miles during these sessions, but as you get going after the first two weeks or so, increase it up to four or five.
As far as lifting goes, I would suggest heavier weights with lower reps for right now. This will help you build strength. As you draw closer to competition (3-4 weeks before the season) I would start lifting lighter weights with more reps, with smaller rest in-between sets. Circuit training, more or less. When you do this, the focus is more on muscular endurance and maintaining strength, as opposed to gaining strength. Generally, I lift three days a week and do a whole body workout, but you can also split your muscle groups into different days. If you decide to do this, I would choose to lift four or five days a week.
Now, for wrestling in the preseason...do it as much as you can. For the rest of August and throughout September, work on what you feel you need to work on in order to be successful this season. Normally, that means eliminating your weaknesses. If one of your weaknesses is high crotch defense, work on it. If one of your weaknesses is front headlocks, work on it. If you need work on tilts, work on them...etc, etc. Some of it drilling, some of it live situations. Another thing you can do is "sparring", which is very beneficial for putting you in situations you might encounter during a real match. It's basically live where neither of you are going full out, win-or-die intensity. Andy Hrovat explains it here in this video blog, I suggest you watch it - http://www.flowrestling.org/speaker/...og-How-to-spar
As October rolls around, I would start focusing less on what you do wrong, and instead begin to sharpen up what you do right. Drill your setups, takedowns, turns, escapes - get them down nice and sharp for the season. Start drilling hard and dedicate a good portion of your mat time to wrestling live. You can do some conditioning besides live wrestling during this time, but don't overdo it - you want to be fresh for the beginning of the season, not beaten up and worn out.