Depending on your lifestyle (normal activity level) your maintenance calories are probably 3000 or higher. If it is 3000 then dropping to 2000 should yield a loss of 2 lbs a week, if you add cardio etc then even more. You really need to nail down your Maint cals and work from there. If you go to low for to long you'll slow fat loss and lose muscle. Whatever the deficit you want (500, 1000 etc) you need to add calories to make up for your workouts, otherwise you may end up with a -2000 day and thats really going to slow you down in the long run.
This may not help but what works for me is cycling my diet, non-workout days -1000 calories, w/o days -500, every 10-14 days 1-2 days at maintenance. If I maintain -1000 every day my weight loss comes to a halt after 2-3 weeks, if I keep mixing it up and never let my body adjust I keep making progress. Does it take forever? Hells yes!! Sometimes I'll go to maintenance every week for a day it just really depends on how I'm feeling and how my progress is coming along. You have to keep experimenting and find what works for you!