1) Bowman Arrow karts feel a lot like a real racing kart. There is no substitute so far. If you have a mix of 6.5 and 9 hp engines you can ballast light drivers to x lbs and heavy drivers to y lbs.
2) If you've got any way to get elevation change, use it. That includes being creative with the parking lot on good days.
3) Indoor karting is addictive. Your job with prices & schedules is to get your clientele hooked and keep them strung out. No "first-timer" fees, ever. Seriously, I'd have a $-10 license fee - ten bucks off your first race for a lifetime license. You can then have them pay the normal price for racing afterwards. It is better to have someone drive their first 3 races for $50 than to soak him for $20 for a license, then $20 for a race, then never have him come back.
4) Your license list is your marketing list! Send out frequent "free first race for a friend" specials. Once again, get 'em hooked, keep 'em hooked.
4a) Not all of your specials have to be advertised. Have someone who's got some business sense in control whenever you're open. If a regular mentions that his boss is trying to find a good place for the Christmas party, and you make the five-grand deal for it, he needs to get some racing on the house.
5) Offer addicts cheap track time on your slow nights. You'll learn soon what day people don't want to go to the kart track, so make that one "Student discount night". Once again, get 'em hooked, keep 'em hooked.
5a) If a timeslot is so poorly attended that not even the student rate fills it, then there's no sense paying people to be there for it.
6) Get people to sign up and prepay for racing. A bird in the hand is worth two in the bush. A prepaid league will get people to go to almost every race. Your championship schedule needs to have a drop or two in it.
7) Friday and Saturday nights need to be packed. Once you're at capacity, then start raising the full-price Fri/Sat rate.
8) Control your overheads, in both senses of the term! A "Little Hitler" race director with an itchy ejection finger is a great way to lose a league driver. While you need to protect your equipment and avoid lawsuits from injuries, indoor karting is where racers try out new moves in traffic and sometimes they don't work. Paying people to stand around is a waste of talent and money, as is building a commercial kitchen to serve ten hotdogs and a cheeseburger a day - get the local pizza joint to deliver when you're busy enough to have a wait to race.