Screen printing wet on wet can save a lot of time. There are some things you should take into consideration before screen printing wet on wet.
1.The first is the artwork, if you are creating the art work then try and make things easier on yourself- for example- set traps and gaps between colors so the ink do no touch. If you are able to design the art so that no color touches then you can print with no inks touching and becoming muddy or blurry. A way to design with this method is to use the color of the shirt in part of the design so that you give yourself breaks between colors or places for inks to fall off the base and onto the shirt with out falling into each other.
2. The next consideration is on press and determining screen order. The most common order to print wet on wet is light to dark. Meaning the lightest color is first on press after the white base, then print the next lightest color all the way to the darkest color.
3. One exception to that rule (2.)- is the size of each part of the print- if the lightest color is yellow- but that part of the design is the majority of the print- and the darkest color (navy blue for example) is the size of a quarter- then print yellow last. So you also want to consider the size of each part in the design.