General advice. Trying to lose 20 lbs.

fantasmagris

So, I've been trying to count calories for a few months now, but I've gained a pound rather than losing anything. I want to work smarter not harder so...
1. Is the 1200 net calories a goal? Do I want to be under 1200 through exercise? What's the deal on that?
2. What sort of percentages should I aim toward in terms of fat/protein/carbs?
3. General tips?
If it helps, I'm 5'8" and 149 lbs with measurements of 38/28/38. I usually do between 10 and 40 minutes of cardio (walking a mile or two, jump rope, stationary bike), between 250 and 400 crunches, and about 40 lady pushups each day.
Thank you in advance,
Em