While preparing wet mount of a specimen using water or Vaseline, following precautions should be taken:
1. use appropriate amount of water or Vaseline.
2. no air bubble should be present under the cover slip.
3. mount should not be thicker as thicker mounts do not produce clear image of the specimen.
4. if specimen is thick, then support the cover slip using a thicker material from the sides.
5. gap between glass slide and cover slip should be shallow.