Help me lose weight?

I would like to drop down 40lbs by September for a family function. I do not eat junk food or candy and am usually very careful about what I eat.

Walking for 40 minutes everyday but it doesn't seem to be helping anymore. It helped me lose the first 20lbs. Walking has been going on for about 5 months now.

Is there a diet anyone could recommend that would help me lose weight? Or certain foods that would help me?
Help me lose weight?
Post Opinion