Understand the Differences Between Bitmap and Vector
For a more complete explanation of the differences, I highly recommend you all read Lesson 3 of CorelDRAW X5 Unleashed. For those who haven't purchased CorelDRAW X5 Unleashed, this lesson is a free download. In order to work in a vector editor, you need to understand why vectors can be beneficial. The reverse is also true. For those who want to get the most out of Corel PHOTO-PAINT or Adobe Photoshop, you have to understand the strengths of an image editor.
Once you understand when to use vector and when to use bitmap, you can choose the right tool for a particular job. Some jobs require a mix and that means you'll use multiple tools to complete the job. Unfortunately it is a massive struggle if you use a vector editor to try to edit bitmaps or an image editor to work with vectors.