There are two ways to screen print with a squeegee, which are either to push or pull the squeegee. Pulling the squeegee toward you is the traditional method, but pushing the squeegee is easier.
Pulling the squeegee toward you is very hard and taxing on your wrist and fingers can become numb and fatigued. Carpal tunnel is also associated with pulling the squeegee for screen printers who have been pulling the squeegee for years. Pushing the squeegee uses your upper body strength and shoulders. This is a much easier and less fatiguing way to screen print. You can get a higher number of shirts printed per hour using this method.
Whichever method you choose to use, whether it be pushing or pulling, just print the shirt with one or two strokes. And always print in the same direction. Never do a push print stroke then do pull print stroke. By doing both a push and pull print stroke you run the risk of a blurry and smeared print.
Flooding the screen is not the same as printing. If you flood the screen you are only loading ink in the screen mesh. Which means it is not all the way through; it should not be peeking out the bottom of the mesh. You are not pushing the ink all the way through the screen when flooding.
You should only be applying medium pressure when printing plastisol ink, if you have to apply heavy pressure your ink may be too thick. Also when you apply to much pressure with plastisol ink it pushes the ink down into the fabric. And this is not what you want to do with plastisol. This will result in dull colors. Plastisol is designed to sit on top of the fabric. This will keep the colors bright and help achieve a more opaque print.
With water base or discharge ink you should be applying more pressure. Water base and discharge inks are pushed into the fabric. So use less off contact and more pressure when printing with water base or discharge ink. Push the ink down into the fabric.