One of the first steps for doing part or all of your own DIY cabinet painting is labeling your doors. Many people think 'Oh, I'll remember where each door goes!'. Ha! Don't forget that the doors are going to look significantly different (or the same) once they return from the spray shop or from your garage.
Thankfully this is one of the easiest steps of the whole cabinet painting process. After wiping all the doors down with warm soapy water (much easier to clean them while they are hanging... and they dry better too!) take small 1" to 2" pieces of green painters tape and place a piece on the outside of each door/ drawer.
Once each piece has tape on it use a Shapie Marker to label each door from 1 to xx. Draw yourself a crude schematic of the layout of your kitchen and label the diagram to mirror your cabinet layout.
The doors are now ready to be removed and transported to where you are painting them or to where they are being painted. (Most time there is no need to remove the hinge from the cabinet itself, just from the door; this makes re-install a breeze.) Most spray shop will continue the labeling process from this point. If however you are painting the cabinets yourself, read on.
Now that your doors and drawer faces are all removed it's time to transfer the labelled numbers to an area where it won't get painted over. The most logical point is the hinge hole.
Once the numbers are all transferred to the hinge hole we cover it with tape so it won't get painted over and label the top of the tape as well in case a door has to be identified prior to painting.
The same process applies to the drawer faces, just be sure the label is in a place that will be covered by the drawer hardware itself. You are now ready to give the doors a vigorous cleaning prior to sanding them.