How to make chapattis round and of same thickness? I have tried making Chapatis many times. I can make dough for Chapati very well, but I am failing when it comes to structure of the roti/chapati.

I make two mistakes:


When I try to flatten it, one side (when you look at it horizontally) is thicker than the other which makes it hard to be cooked evenly and results in a chapati that no one wants to eat.
Chapati should be round, sometimes I am lucky, most of the times it is similar to map of Australia. Is there a trick to keeping the chapati all uniformly round?
If you are having trouble rolling dough to a uniform thickness then you might consider putting training wheels on your rolling pin until you get more practiced.


http://www.amazon.com/Rolling-Hills-Pin-Rings/dp/B000I1ZXBC
(I don't know anything about this particular brand.)  

These rubber bands fit on your rolling pin and act as spacers so you can enforce a strict thickness upon your dough. They are, of course, useful for rolling out many things besides chapati.

To reiterate what @rumtscho and @bob said. Your dough should be of a uniform consistency if you want to roll it out in a uniform manner.

As far as a perfect circle goes, turn it often and don't roll too much in one direction. It just takes some practice.