Part of your body image derives from your level of muscle tone.
Muscle tone is also called definition and having good muscle tone or definition means that you can see the outline of your muscles under your skin.
There is a layer of subcutaneous fat between the skin and the muscles, so if that layer of fat is too thick, the muscles will not be visible, no matter how strong they are.
That layer of fat is also what gives the skin on your buttocks and thighs that cottage cheese appearance, so working to get rid of it will also make you look much better in a bathing suit.
Having good definition takes both fat loss and muscle building.
The good news is that fat loss becomes much easier as you increase your muscle mass, because muscle burns calories at a much higher rate than fat.
All exercises contribute to good muscle tone, so there is not any special set of exercises you should be doing to increase your definition.
Aerobic exercise or cardio exercise helps burn through that layer of subcutaneous fat that can hide your muscles if there is too much of it.
Strength training exercises or resistance training exercises build muscles, increasing their mass so that they will appear clearer when the layer of fat is gone and the muscles are visible.
Stretching exercises increase the flexibility and elasticity of muscles.
There is no magic way to get rid of fat and build strong muscles, but it is also not that difficult.
If you are overweight, you must consume fewer calories than you expend in order to lose the excess weight.
Whether you are overweight or not, in order to gain clear muscle definition you must exercise and build muscle mass.
A carefully planned program of exercise and close attention to diet and nutrition will help you reach your "dream" body.