I wrote this a while back when someone else asked the same question.
There are loads of ways of rolling a J, and everyone has there favourite.
I like this one as it makes it easier to do the actual rolling 'cos
you have a double thickness of paper in the middle so it stays straighter,
but that has it's drawbacks as you're obviously smoking a bit more paper.

Anyway .......

      Fundemental Social Skills - Revision 1.0 - Joint Rolling
      --------------------------------------------------------

Everyones got there own way of sticking a joint together, but here's
my favourite. You get a little more paper in it than is completely
necessary, but it's pretty easy to get a decent looking J.

Start off with two normal sized rolling papers - remember those, the
really little one's that those strange people with the yellow fingers
use. This method also has the additional advantage that when buying
your papers you don't have to do that, shuffling feet motion and
looking really embarrassed while asking for "some king sized super
reefers please". Advanced users can try it using king sized paper's
instead and the results do look quite spectactular. Anyway, I digress,
start off with two normal sized rolling papers, like so :

         ################################################
        |                 |          .                   |
        |                 |          .                   |
          -----------------------------------------------
        |                 |          .                   |
        |_________________|__________.___________________

the dots are the end of the paper at the back.
The hashes are the sticky on the papers.

Then add a third paper to the back of both of them to keep it all
together like this :

         ################################################
        |                 |          .                   |
        |                 |          .                   |
          ---------##########################------------
        |          .      |          .      .            |
        |__________.______|__________.______.____________
                   |                        |
                   |________________________|

and fold the sticking out bit (technical term that one -
remember it) back into the center of the papers, like so :

         ################################################
        |                 |          .                   |
        |                 |          .                   |
          ---------##########################------------
        |          |                        |            |
        |__________|________________________|____________


So if we cut out all the unwanted detail, from the top it should
look like this :

         ################################################
        |                 |                              |
        |                 |                              |
          ----------========================-------------
        |          |                        |            |
        |__________|________________________|____________


then add you gear into the fold in the middle, leaving space on the
right hand side to put your roach (slight note on terminology, I use
roach to mean the bit of cardboard you bung in the end, I know some
americans use it to mean just the end of the spliff). If you're using
hash, you'll obviosly have to add some backy or weed or whatever to pad
it out, roll it, lick it, stick it, slide in the roach (ie roll up a
piece of a train ticket or similair bit of thin cardboard and shove it
in the end so you don't end up eating the gear, or cooking you lips),
and smoke it.

A couple of tips for rolling, worry about keeping the roach end tight
to start with, because you can always just force all the gear down one
end if it's too loose and have a short fat carrot. Secondly, it helps if
your fingers are just a little bit moist, because then they grip to the
papers better. Other than that, whatever way you use to put your papers
together, it's just a matter of pratice, and you can always do that
with just tobacco, which is generaly a lot cheaper (then just break it
open and try again, you don't have to smoke them :v). Oh, yeh, if you
use tobacco in your joints (which does tend to be the case in the UK
because we tend to get hash), I find rolling tobacco is easier because
it sticks together easier, rather than using the contents of ripped
open cigarettes. It does go out easier though, so you just have to keep
sucking on that baby (what a shame).

--
   Descartes thought an animal,          _     .
   That couldn't talk,                  /##.,.##\          Glyn Hanton
   Couldn't think, or so he taught,    #### ######
   But to summise,                     ###@   @###     glyn@crosfield.co.uk
   My cat thinks otherwise.             ##/ v \##
                                          ` ~ '