think about perspective... for that real focus fall off you want the subject nice and close to the camera, and the distance between the subject and the background at least double that of the distance between the subject and camera, ideally even more.
Think about light... your guy is in the shade, no catchlight = dead eyes.
Look into fill flash, the wee pop up flash on the 1100D is actually fine for a little bit of fill flash.
Post prod is important as discussed.
Think about colour profile, are you going to be primarily printing it (use Abobe RGB) or sharing it online (use sRGB)
Think about a little post sharpening and NR on the RAW files. Can help make things POP a little if used in a subtle way.
Nothing wrong with cam or lens, should actually be a pretty good combo for portraits.