I have tried deleting vertices, but that doesn't work. Is there another way to hide this problem?
If you are using Blender, another option would be:
1) Select the clothes; 2) Go into Sculpt mode; 3) Choose the Inflate tool from the tools on the left, and then blow up the clothes a little bit, so it covers the body; 4) Repeat step 3 for all the exposing areas.
If you want to keep the model underneath, use the Mask Modifier to hide the unwanted geometry.
Create a Vertex Group and Assign with a strength of 1.0 on the parts of the mesh you want hidden, name it whatever you want. Add the Mask Modifier and choose the Vertex Group.