It is totally impossible to describe how to roll a perfect smoke in words, you have to see it. So I won’t even try. Over the years, I’ve learned to roll an absolutely perfectly cylindrical cig. Everyone who sees one is amazed. The only thing I can recommend is practice practice practice.
The best thing I can suggest is to get a soft shag tobacco that’s easy to roll, my favorite is Three Castles. When I first started handrolling, I used to buy Dunhill Flake, nobody told me it was a pipe tobacco!