how to make great portrait

It's not so much the camera as the photographer. I suggest checking out a book on portrait photography from your library and copying their technique.

You can shoot a great portrait out of your kit lens, use off camera flash, good lighting, compose your portrait beautifully and set your set your lens to it's sharpest setting, 3 stops down from it's widest opening.

I have the very same camera, the 550D (also known as the T2i) is a great camera for the cost. I also have the very same KIT lens as yourself. It's not all about the lens, although it would be great to have a better lens, it can cost so much. The kits lens isn't all that bad, it's actually quite the good all-round lens! It's not 'best' at any one thing individually, but it's definitely good at everything. All around good. So, for portraits, one thing with dealing with lower quality lenses, even though you have a decent lens and camera, is the lighting. Make sure you have soft, diffused lighting so that there is no harsh shadows and brightness on their face. Sometimes people, if they are smart, put more money into their lighting setups than into their cameras. Spending more than $400 is not that uncommon, although there are some good deals on amazon, such as this $56 lighting kit. http://rhinofeed.com/lightingkit