A new goal.

So after graduating high school I wasn't involved in any sports programs which were my main sounce of excerszie. In result I have gained about 30 lbs over a 2 year period. I wasn't fat at 160 lbs but I have lost a lot of muscle tone so to be at a good size i estimate that I will need to lose an additional 10 to 20 maybe even 30 lbs. Three months ago I started my diet at 210 lbs, I am now down to 185 lbs equaling a 25 lb loss. Any tips on losing weight?