Drawing can be tricky in photoshop. It is generally easiest to draw something out of basic shapes like I'm going to demonstrate here. This flower will be created from simple ovals and circles.

This tutorial will help you create a three dimensional can in Photoshop.

This tutorial teaches you how to make a 3D background for your images.

Text is probably the easiest type to achieve a 3D effect. This tutorial explains how to achieve a 3D look with only 2 layers.

Learn how to make embossed 3D logo with pointed edges.

Editor's Pick in Photoshop Tutorials, June 2007
This article for Photoshop shows you a good way to create a 3D Polaroid. You take the simply explained steps provided here by the author and then you can push them as far as you want to go to attain a fantastic effect.

Editor's Pick in Photoshop Tutorials, June 2007
Here's a very good tutorial in Photoshop to build an Image Cube. This effect has many applications - yet it is not a complicated study. The author writes brief text and adds a picture to see an example - and the product is cool.

Yet another 3 dimensional text effect.

1. First of all open a New Document here I have selected 300 Pixel / 300pixel. Now from the Custom Shape Tool seelct a shape that look like a jigsaw puzzle piece.
2. Select Pen Tool , and Right click on the shape > Make Selection > click ok at 0.2 pixel.

Learn to create 3d objects.