I personally use Fireworks to create my standard images and use photoshop to touch them up with reflections or things that would be too time consuming to do with shapes.

Also if your wondering about images then i do sometimes use free clipart etc to blend in with the image (say i wanted a pic of a dog) I wouldnt waste my time and taking a picture of everything i needed when theres loads out there to use.

The truth is that you need to mess around with the programs to achieve the best results, but i would personally read a few tutorials of the basics, such as shape creating, effects etc.

www.tutorialized.com has alot of them.