Reading 17th and 18th century documents has its quirks. When working with these resources, remember to look for these options:
Variant spellings: Before the standardization of English, many words had a number of alternate spellings. Check to see if your database has a variant spellings feature, or enter variants manually.
The long S: This symbol ſ was used when S appeared in the beginning and middle of a word.
U and V: These letters used to be interchangable, with v appearing at the beginning of a word and u in the middle.
Dates: Some databases may permit searches outside of your date range, so take care to limit dates if necessary.