How much weight should I lose?

Read these:

http://community.myfitnesspal.com/en/discussion/1080242/a-guide-to-get-you-started-on-your-path-to-sexypants

http://community.myfitnesspal.com/en/discussion/10012907/logging-accuracy-consistency-and-youre-probably-eating-more-than-you-think

http://community.myfitnesspal.com/en/discussion/819925/the-basics-dont-complicate-it/p1

http://community.myfitnesspal.com/en/discussion/872212/youre-probably-eating-more-than-you-think/p1

http://community.myfitnesspal.com/en/discussion/833026/important-posts-to-read/p1

Goal setting, including weight, calories, and macros
http://www.myfitnesspal.com/blog/MKEgal/view/2014-06-08-setting-goals-667045

As a comparison, I'm 5'10"-ish in the morning, and my top healthy weight, based on BMI, is 175.
I'm aiming for 160, and might possibly go as low as 150, depending on how I feel & look, but am
not planning on that.

So you're not too far above a healthy BMI range. 168 lb would make your BMI 24.9, which is the top
end of the healthy range, and you'd need about 1450 cal/day if you were inactive.
See this calculator: https://www.bcm.edu/cnrc-apps/healthyeatingcalculator/eatingCal.html

You might do better to focus on weightlifting, body recomposition, rather than losing weight.
See this site: http://www.bodyrecomposition.com/
You'll lose a little weight along the way, but your measurements, shape, and overall appearance will
change dramatically.