I was asked recently what my technical process was when preparing tilesets in Adobe Photoshop, so I thought I'd share some insights / tips which make my life a lot easier. Feel free to ask questions in the comment section should you have any!
As a Photoshop user you might be familiar with Guides, if you use InDesign a Grid might be more familiar. Photoshop also has the option to create custom grids (which can be activated/hidden by pressing CTRL/CMD+'). When creating Pokémon-inspired tiles I follow the 16x16 pixel rule. Which means the tile needs to fit within these boundaries so that they may be used in the creation of maps, by myself or others.
To set a custom grid follow the below path:
Preferences > Guides, Grid & Slices
I then change the values in the 'Grid' section to match the image below:
Which creates the following result when activated (CTRL/CMD+').
When paired with a 16x16 tile-sheet background you can see how the Gridlines follow perfectly. Your canvas