Nice to see you here!
My experience with sudoku is that there's a few methods or mechanisms to use and in time you just work out (intuitively) the best way to sweep through them.
As for sites, I don't know... if I play sudoku it's on my Nokia phone, in the Brain Chamber game. That's a decent game except that there's no delete (that I've found yet) for if you realise you've put in the wrong number.
"Do not force others, including children, by any means whatsoever, to adopt your views, whether by authority, threat, money, propaganda, or even education." - Ven. Thich Nhat Hanh
"The uprooting of identity is seen by the noble ones as pleasurable; but this contradicts what the whole world sees." (Snp 3.12)
"To argue with a person who has renounced the use of reason is like administering medicine to the dead" - Thomas Paine