Work on your abs and obliques with these core exercises for women. A 30 minute waist cinching workout to activate your obliques and define your waistline! http://www.spotebi.com/workout-routines/core-exercises-for-women-abs-obliques-workout/
The seated leg lift, with or without weight is a great lower ab exercise that you can do at work or at home. You want to keep a slit bend in the knees and lift until you feel it engage your lower abs. This is just one of the simple exercises that you can do without the aid of a guy.