Center the slide so that the specimen you hope to view looks like it’s about centered in the light.
Using the smallest objective (usually 4X), adjust the slide so that the specimen is within your field of view.
Using the coarse adjustment knob (the big one), bring the stage closer to the objective lens until the object is focused. If you cannot focus the image, bring the stage as close as possible, then use the fine adjustment knob to continue focusing the image. You should now be able to bring the image into focus.
6 of 8
How to focus (cont)
Now switch to the second objective (usually 10X). Do NOT touch the coarse adjustment knobs anymore. Use only the fine focus to bring the object into focus. If the object is no longer centered in the beam of light, center it.
Once in focus, if possible, switch to the third objective (usually 40X). Again, do NOT touch the coarse adjustment knobs anymore. Use only the fine focus to bring the object into focus. Center as necessary.
Finally, add a drop of lens oil to the microscope slide where the beam of light is going through. Switch the objective to 100X and use the fine focus knob to bring the specimen into focus.
7 of 8
How to make a wet mount
Place the specimen in the center of a glass slide.
Cover it with a clean coverslip.
Using a pipet, place a drop of water on the edge of the cover slip where it touches the glass slide. Use a small piece of paper towel on the opposite side to pull the water through.