I'm a big fan of field search tags. So, for example, typing in
Lee S [au]
will give you all authors whose name contains "Lee S". But typing in
"Lee S" [au]
will only give you authors actually named "Lee S". Furthermore, if you know what university he/she's at, you can use the affiliation tag, so that typing
"Lee S" [au] AND yale [ad]
would only give you a Lee S at Yale. If you, for example, wanted this guys articles from back when he was a postdoc at Harvard, then you might type
"Lee S" [au] AND (yale OR harvard) [ad]
Another useful one is [ta] which is for the title of the journal (make sure you're using MeSH abbreviations). So, typing
"Lee S" [au] AND (yale OR harvard) [ad] AND (science OR nature) [ta]
will give you articles by Lee S published in Science or Nature either during his time at Yale or Harvard.
I'm sure you get the point. 😉
Check out PubMed's Help, it's pretty helpful.