230 to 170 in about 6 months? That's going to be pretty challenging. I did something like that in roughly 5 months but I didn't give myself room to mess up nutrition wise, some days I was doing up to 3 hours of cardio and had to force myself to stop, and there was no chance I was going to lose my motivation.
So here's the really short version of what you need to do. If you'd like for me to expand on different things I'd be more than happy to:
You need to be in a caloric deficit, that's the only way you lose weight. It doesn't really matter what you eat as long as you're in a caloric deficit. Your diet could consist of fried twinkies and double quarter pounders, so long as you expend more energy than you take in you will lose weight.
To get into a caloric deficit you need to get an estimate of maintenance calories and subtract from there. Normally 10-20% of your maintenance is sufficient, however, the bigger you are the bigger of a deficit you handle.
Exercise isn't necessary but will greatly improve your likelihood to succeed as well as generally speeding up your results. Cardio is going to be your bread and butter, and don't get lumped into the trap of running the treadmill if you hate it. Swimming, dancing, playing DDR, jump rope, basketball, and so on are all wonderful ways of getting in cardio. Find something you'll enjoy doing otherwise you're going to burn out and quit. You will also benefit greatly from incorporating strength training as well.
Fix your sleep schedule. Make sure you're getting between 6-8 hours every day.