secretary -|- Your secretary will keep your secret! 

separate -|- If you split this word up you will separate the -sep and the -e with a rat. 

supersede -|- This word supersedes other words, it's the only word in the english language to use -sede  
 

sandal -|- Sandals are perfect for the sand. 

sandwich -|- No tricks here, make a sandwich out of the words sand + wich ßwhich isn't actually a word.  

savvy -|- Savvy is so savvy it needs to V's. 

scissors -|- 3 S's in this word with a c tagging along. 

siege / seize -|- although they sound almost exactly the same with different consonants, there's no trick to remember that one, siege, follows the –i before –e rule and one, seize, does not.

shepherd -|- This word is easy, just remember a shepherd leads a herd.  

sheriff -|- 1 r, 2 f's and an –e making that –a sound.  

sincerely -|- To make sincere an adverb, simply add the –ly.  

subtly -|- Like with debt, the –b in subtly is silent.  

sacrilegious -|- Although it may sound as though religion is in this word, it's not. When spelling sacrilegious, invert the –e and –i from religion, drop the –n and add an –ous.  

schedule -|- School Causes Headaches. Education Delivers Unnecessary Lulls In Excitement 

sergeant -|- Break it up: serge – ant  

similar -|- Sometimes I Might Imagine Lurking And Roaming 

surprise -|- Your surprise won't be worth much if you forget there are 2 r's in this word and not a single z.