This is the first worksheet that's included in the "Commonly Misspelled Words Lesson Plan" bundle. (Get the bundle and save $0.50. and have an entire class period filled.)
This grammar worksheet contains 29 different words, including "there/their/their", "your/you're", and "where/were/we're". It has two sides, one with the words, one practice side.
The first side is divided into three columns: the first gives the word (with its part of speech); the second gives tips/explanations on how the word works; the last column gives an example sentence with the word.
The second side is a practice side, containing 18 sentences. Each sentence has one or two blanks as well as a multiple choice set of answers. Of course, students must choose the correct word.
I use this in just about every English class I have, either for practice or after an actual lesson and can easily fill up half of a period.
Here's how you can use it: Review each word, its part of speech, its rules and examples with students. There are 29 distinct words, so this will take a few minutes. Then, do the first question on the practice side together. Give the students a few minutes to complete the exercises. Afterwards, review it by having students go to the board and write their answers. Review the answers on the board, explaining/correcting things as you go along. At the end, if you have a minute or two left, quiz the students orally by reading the example sentences and asking them to offer the correct spelling of the word.