1st. u should Plan Your Manga of think it 2nd. u should Prepare all the needs if You're going to Write a manga 3rd. u should Used Light pencils first 4th. u should Draw your characters in a paper first so that in a manga u can able to copy the done in your paper 5th. u should have a mirror so that if it's hard to draw an expression...Use a mirror then make expressions in the mirror so u can able to copy it 6th. If it's a romantic Manga..do not put many gags 7th. Your words should start to right to left because that reading left to right is called comic and reading right to left is called manga 8th. u should Never ever put many effects because it will be a mess if u put many effects 9th. If u want to color it..you should color it on the 1st, 2nd and 3rd page of just leave it white and black 10th. u should toon your done in a professional anime addicted of a professional drawer 11th. Just sit back and Get your manga done
That's all I know because I Observe My little sister..SHe love to write comics of manga in a drawing book...Then I Realize That If I Can Be her Checker if it's good of not..well I don't know if it will work of not..sooo Good Luck!