The increasing order of nucleophilicity of the following nucleophiles is:

CH3SO3-: The negative charge is highly delocalized over three highly electronegative oxygen atoms via resonance. Because it is incredibly stable, it is an exceptionally weak base and a very poor nucleophile (often acting as an excellent leaving group).
CH3COO- : The negative charge is delocalized over two oxygen atoms. It is more basic than mesylate, making it a moderate nucleophile
OH- : The negative charge is localized entirely on a single oxygen atom with no resonance stabilization. Therefore, it is a very strong base and a strong nucleophile.
H2O : Water is a neutral molecule. Neutral nucleophiles are significantly less nucleophilic than their conjugate anionic counterparts OH-.