1) Step one is the hardest step of all - be sure to an only child, and the offspring of itinerant HGV driver and the village outcast. Ideally, you will only have a cursory interest in both receiving and delivering the spoken word.
2) Hang around working quarries, waste depots and the like without wearing safety goggles - some kind of eye disease is vital.
3) Do not have an eye for details - if you possess one, discard it like you dispose of a mars bar wrapper while indulging your 30-a-day habit.
4) Sniff heroic amounts of glue between the ages of seven and forty three.
5) While sketching your first attempts at creating a manga masterpiece... a mangapiece, if you will - do it in the rain to get that authentic manga look (if the wind is above 30 MPH, all the better).
6) If the storyline is too linear, rearrange the pages and turn some of them upside down.
7) Most modern mangas that have been heard of outside the author's family have a rape scene of some kind. Just sayin'.
8) Publishing houses are stuck in the 18th century - all successful and original manga is distributed online (in much the same way as the music industry - if a musician releases his material solely online, it's regarded as the pinnacle of achievement by his peers.)
9) Don't dwell too long on the material - there's a reason why most manga looks like it was tossed off in a matter of minutes (ie, it was).
10) And finally - do not be put off by the sneering and derisory attitude of 'the world' as you paste pages of your mangapiece around areas of your local parish. Time will either vindicate you, or forget all about you.
