Base used in tutorials are from Xandorra
Extra Advice: Best Done on maximum zoom

First and foremost, is to have two sets of the base you are using (by copy+paste the other base somewhere else. This is so that whenever you make mistake you can rectify it easily.You can do this everytime you add something new) Anyway, first step is to draw the outline out. Don't worry about details, you can do that later.All outline must be in single pixel. It'll look nicer that way ^^

Now add the colour (indicated by arrow) everywhere inside your outline. This would be the basis colour of the dress and corset

Now this next colour would be the basis highlight for the dress. Colour it in without going over the outline and the basis colour. Refer to picture for more info.

Now add the last highlight. Caution: Do not highlight practically everywhere, imagine a light source shining down on your dolls or in whatever direction. Draw your highlight according to that Always add highlight to the parts where it is going outward. inward parts should be coloured dark (that's a 3D basic)

Now is the time to add details! ^^ you can add whatever you like. But usually in corsets you should have some form of string or strap instead of buttons. Here i have also added details on the sleeves and on the folds of the skirt -> adding details at this area would usually help to define your folds even more, therefore it is always a good idea to add details in this area if your doll has no patterns

it is important to shade details too. i have seen dolls with details not shaded. Use your dress highlights as guideline

it is always best to shade details in minimum 3 colours. (Darkest = details outline, middle, and lightest)

Here's the completed doll. Follow on to hair tutorial to get a full doll!