Gaining weight is easy...any tips on losing?

Ok ok...so we've all heard "eat less, exercise more!" I get it! My question is, how do you get motivated to workout more? How do you pass on the ice cream sundaes when everyone else around you orders one? I've slowly gained 25 pounds and I need to get it off!! I'm going insane trying to figure out something that will work for me! I'm 24, 5'10'' and now 210 pounds. My most comfortable weight is 185...help a girl out!!