help to reduce noise!!

Hi people,

I am layout a board. I do not know how get a good layout board. I know
that the layout process plays a important role for reducing noise. I
need a board with the minimum noise. I read some document on the
internet, i separate the digital area and high current area. i try to
tied all ground together. I hope it will decrease the noise. Can any
body know more ways to reduces noise when layout?

Please tell me, if you know
Best regards,

Him Lam