Using Scratch can be fairly complicated at first, which is why I've decided to start a sort of post series, for members of the site. This is the first of the series, though the post detailing the Dragonet Maker does fall into it, and technically, before it. We'll call it a prequel.
Anyways, as you can tell from the title, this first post in the Scratch Coding series, will be how to make a simple Dress-Up. I'll be using a game I made some time ago for a reference. If you would like to play the game, you can find it here
Alright, the first thing you're going to want to do after opening up the platform you'll be using, either the online or offline version, is to create a base sprite. This will be your dress-up person, so go as fancy as you want. Just make sure there is no hair, you want your players to be able to add hats and wigs as they please, or even leave them bald. You want to be able to give your players lots of options!
Once you have the sprite made, drag it to where you want it and into the code area add the When Green Flag Clicked, and under it attach a go to X: Y: piece, putting in the coordinates of where you have the sprite.
Once you have that done, copy the sprite. Go into the costumes tab, and draw your first outfit over the base sprite. Once you have it completed, erase any parts of the base sprite left over. Repeat this step until you have all the costumes you want, and then do it again for hair, shoes, and accessories.
Once you have all the costumes you want, drag them all into the places you want them in, and edit the code that should be there. Then click the little blue circle with a white i in it, and click on the box by 'Can drag in player'
Congratulations! You're done.
If you want to add a background and special effects, that's up to you.
What kind of dress-ups have you made in Scratch? Care to share a link? I'll do my best to comment on them should you link them