Just got a Rebel T4i with a lens kit. Will be using for product photography (clothes), will be resizing images to 5'' x 5'' to fit on online webpages. (FYI I have a light kit ordered should come in this week).

(1) It came with two lens:

Canon EF-S 55-250mm f/4-5.6 telephoto zoom lens

Canon EF-S 18-55mm f/3.5-5.6 IS type II lens

Which lens should I be using? Guessing the IS one.

A guy who had some kick ass pictures...I asked him what he used and he said an older canon (don't remember the name but it's from 2006) and Canon EF-S 17-55mm F/2.8 IS USM Lens. That lens is $800+, I don't mind buying it, but people have told me I wouldn't see a difference between my lenses and his lens (for my purpose)... true or not?

(2) My camera came with some software like Adobe Photoshop elements 10, but someone recommended Adobe light room (which isn't too expensive). Should I invest in it? What adjustments should I focus on in photoshop (probably impossible to answer)

(3) How should I be shooting? Someone just told me shoot in RAW mode. Other than this, is there any other settings or adjustments I should use? (Yeah, never used DSLR before). I know there are photo books out there (100s of pages), is a lot more detail than I want or describes multiple functions. I am just using my camera to get rid of some old clothes, usually list for charity, and get whatever I can out of it. Not looking for anything else (maybe some day).

Any thoughts and opinions are appreciated (: