Visit the main Customisation Spotlight spotlight page (or the “Enter” page) and you will be shown a list of your Neopets, with the option to check a box to enter them into the Spotlight. They will be automatically sorted into their appropriate category, so you don’t have to worry about figuring out what they’re wearing.
If your Neopet is eligible to be entered in the contest, then you can check the box. If they are not eligible, then the box will be greyed out and you cannot enter your pet in the Spotlight.
All spotlights can be entered each week, and up to 2 pets can be entered in each one. You will only be able to enter a single pet into one spotlight at a time. That means that you cannot submit the same pet into both the regular weekly contest and the monthly themed contest; you will have to pick one or the other. You can, however, enter 2 pets in the Weekly Contest, and then enter 2 different pets in the Themed Contest!