I'll share my work flow for creating monster stat blocks. Doesn't require any HTML knowledge. End result is a PNG image file. Thanks to some very enterprising programmers on the web!
Step 1
Get Valloric’s Web Component for 5e statblocks:
http://valloric.github.io/statblock5e/
Step 2
Navigate to this handy Challenge Rating Google spreadsheet:
https://docs.google.com/spreadsheets/d/1VV8ebSREn0fpw8YtNe-5s5YGJYoF3DK1tB0eLyXRobk/edit#gid=0
Tip! You may need to make a copy of the spreadsheet in order to edit it.
Step 3
Input your monster’s information in the spreadsheet, using the DMG pages 273-283 as a guideline.
Step 3
Copy the HTML statblock (from the spreadsheet) to a plain text editor like TextWrangler or TextEdit, and save it as a HTML file.
Note: If you’re using TextEdit on OS X, make sure to go into Preferences and set the format to Plain Text.
Step 4
Open up the saved HMTL file in your Chrome browser.
Step 5
Take a screen capture, and either import the captured image directly into your document, OR clean up the edges of the image in Photoshop/GIMP using the magic wand tool first and then import it into your document.
Tip! If your stat block is so big that you can't get a good quality screen cap of the whole thing, then divide it into 2 screen caps and merge them in a graphics editor program.
Optional Step 6
If you want to make an entire page in Photoshop/GIMP resembling the Monster Manual, download the Statblock Page Resources:
https://mega.nz/#!DMcEhRQI!RdV02Wqy4hThUxcxQVg1_pz_OGZARFgibZ38moSc5p8