Terracotta planter... ready to go. You can find these cheep. I purchased Patio Paint to help the pot be weather proof. Paint planter all over the outside.
Sand with sand paper to give a weathered look - not so perfect... no rules to this.
Find a good font and print it out the size you want it to appear on your planter. Make sure it's thick enough to make it easy to paint on your pot. For the "M" I used 2Peas Renaissance.
Now for the fun part... turn your print out over. Color with a white crayon all over the back of your letter.
Affix your monogram exactly how you want it to appear on your pot. Use small piece of double sided tape to keep it in place. Take an ink pen and with pressure - trace around the letter.
This leaves a white outline of the letter... so you can paint with in the lines.
Using small paint brush with rested eyes - do this when you're not in a hurry for best results - paint in your letter. You may have to use two coats of paint.