How to write a puzzle...

Having just written in passing in another forum about writing puzzles and how hard or difficult it is, I wondered if there are any puzzle writers here?

It would be interesting to find out what the process is or rather should be for creating a puzzle.

Particularly with a puzzle like sudoku since that is one we are all familiar with: is there a set way to fill a grid to increase the chances of it having a solution?

Or do you literally just plonk in, say 27 numbers, and hope for the best when solving, then add in numbers as you go until you are able to get a solution if initially there is no solution.

Or is there some more science to it than that... I have read somewhere that many computer solvers start from a filled grid and solve repeatedly taking out numbers until no solution can be found: but I can't imagine that a human has the time to basically solve a puzzle 50 or so times, so I suppose that there must be a better way for a human puzzle maker to create a sudoku puzzle?