The more space you have the easier this is - firstly you can throw more light at the background to even out creases is your material of choice without it bouncing back onto your subject, and secondly the longer lens you use, the smaller your background can be, to the point where if you're using a telephoto your background only has to be just bigger than your subject.

Zack arias has some blog posts and videos that give some good advice on working with seamless white backgrounds:

• White Seamless Tutorial :: Part 1 :: Gear & Space

• YouTube: Lighting White Seamless Pt. 1

• YouTube: Lighting White Seamless Pt. 2

• FStoppers: Learn The Many Uses of White Seamless with Zack Arias

However it's gear heavy. Everyone says you need a minimum of three lights to do this, one for the subject and two to get even lighting on the background, like so:

However when I was first doing this sort of thing on a budget (with a white sheet background) I found I could get away with two lights (one background light) because that was all I had! Here's the setup I used:

The problem here is that you can sometimes see the lightstand poking out from behind your subject:

This is easy to fix in photoshop as the background is pure white! Likewise, the edges of the sheet can be fixed.

...leaving a final version, which looks expensive but was in fact a very cheap setup: