on 09-27-2011 12:25 AM
Shoes are in the clothing category. See here for tutorials:
on 09-27-2011 06:28 AM
Almost all good shoes in SL today are sculpties. A few are mesh objects, but those are very new and scarce. To make either of those means developing some skill with a 3D modeling program like Blender or Maya and then importing your creations to SL. Many modelers offer kits of sculpty shoe parts in Marketplace or in-world shops that you can use to assemble your own shoes, if you don't have the modeling software or the skill (or time) to make your own. It's also possible to make prim shoes, which is the way all shoes were made until about 3 years ago. You can find many of those in freebie shops. Pick up a pile of them, dissect them to see how they work, and try your hand at using the general design principles to make your own.
on 09-27-2011 07:46 AM
There are two types of clothing in SL - system and object.
System clothing can be created in SL just by clicking on yourself and using the 'appearance' options. It is 'painted' on the body and so "flat" - heels for shoes are a problem, for instance. Although system clothing is easy it is very limited.
Object clothing - such as most shoes - is made the same way you make any objects in SL. Using 3D prims that are either basic, sculpty or mesh. Basic prims are just made in SL, sculpties need an external graphics package (eg; GIMP, Photoshop) or, preferably, a 3D modelling application (Blender, 3DS Max).
Once you can make something in SL you can nearly make anything.