Make sure that your stamp is clean (no lint, fuzzies, glitter, etc.) by dabbing it with painter's tape to remove any residue.  Sometimes they have a "film" on them from the manufacturing process and you want to clean that off.  Wash it with soap and water and rub gently with an old washcloth or LIGHTLY sand it with fine sandpaper. Stamp on practice paper to make sure that you get a clean image.

Always stamp on a cushion or mousepad.

Use dye ink.  I have gotten the best results with Ranger Archival Sepia or Black or any Memories dye ink.  Marvy is sometimes too wet for me.  Some stampers tell me that StazOn works for them.  Experiment to see which ink works best for you.

Sometimes a brayer works well.  Ink it up and roll it across the stamp in every direction until the stamp is inked.  You don't want it too juicy!  Practice this.

Stamp with even pressure and do not rock the stamp.  you can walk your fingers around the stamp and/or gently rub the back of the paper making sure that you have even coverage.  Peel the paper off slowly from corner to corner rather than lifting the stamp off of the paper.

Allow the image to dry or set it with your heat gun.

You can color your image (when dry) with chalk.  Cotton swabs or make up applicators seem to "scratch" the image.  I prefer using tiny pom poms.  You can buy a cotton picker from your local stamp store or go the the hardware store and get an alligator clip to hold the pom pom.   Both work great.

You can also color your image with ZIG Photo Twin markers.  These are sold to color photographs but they work great for photoart images also.

ALWAYS clean your stamps when you are done stamping.  You don't want any dried ink ruining the crisp image the next time you stamp.