On a workout regime to lose 20 pounds in 2 months

Any tips from anyone am a vegetarian and there's not much activity throughout the day. 
I have started 30 day ab challenges, push up challenge and squat challenge. Other than that I do cardio for 20 minutes almost daily. 
I don't eat junk not do I like anything sweet. 
I have been having vegetable juice and fruits. 
I want suggestions if I could improve my routine any how. I really want to lose 20 pounds. I have my sisters wedding in mid September. 
Thank you.