Select a dress by clicking on it in the available items, then drag it onto the girl's avatar to apply it.
Yes, you can change the color by clicking on the color palette next to each dress item and selecting a different color.
Navigate to the 'Accessories' section on the left side of the screen, select an item, and drag it onto the girl's avatar to add it.
No limit exists. You can add as many items as you like to create the perfect outfit for each girl.
Once you are satisfied with the outfit, click the 'Complete' button located at the bottom of the screen to finalize the look for that girl.