Unless you have arranged for a special "themed" shoot with unusual or over-the-top outfits, the following recommendations can go a long way towards helping you look your best in print.
Try not to have your hair cut too close to the date of the portrait session. Most hairstyles look their best when they have had time to grow out a bit.
The most versatile makeup is low-key and fairly neutral. In fact, many glamorous or theatrical makeup jobs create much more trouble than their worth. Of course, if you are interested in doing a special themed shoot (goth, cyberpunk, glamour/fashion, or whatever) then most of this advice goes out the window. For specialty photo shoots I may recommend retaining a professional makeup artist.