Adding Coverslips 
It is essential that the 
sections be completely immersed in water so that air is excluded.
Air bubbles or spaces will interfere greatly with your observations. To avoid these when adding a coverslip do the following.
a] Place your sections in 2-3 drops of water or stain in the center of the slide.
b] Use a fine forceps to pick up a large cover slip (20 x 40 or 20 x 50)
c] Place one end of the coverslip on the slide (near boundary with frosting) without touching the solution containing the specimens.
d] Steady this end with the fingers of your left hand.
e] Slowly lower the forceps until it touches the slide. By this time the coverslip should have touched the solution on the slide.
f] Slowly remove the forceps so that the coverslip is gently lowered into its final resting position.
g] Remove excess solution by touching the side of a Kimwipe or paper towel to the narrow edges of the coverslip. Be careful not to drag out your sections with the excess solution.
h] if you have been using a stain, add water to one end of the coverslip while withdrawing the stain at the opposite end with a Kimwipe or towel. In most cases you do not need to get all of the stain out.
i] Wipe excess fluid from the bottom of the slide or it will stick on the stage and make your life more miserable than it already is.