Avoid misplacing modifiers.
A modifier, as you might suspect, is any phrase, adjective, or adverb, that modifies a word. Misplacing it results in ambiguity of meaning.
1. During this year, a new organization was founded at our college called the Chess Club.
Is the college called the chess club? No.
For clearer rewrite: A new organization, the chess club, was founded at our college this year.
2. I only saw him yesterday.
Possibly this sentence expresses what you meant; probably it does not.
Consider the differences in meaning of the following sentence.
Only I saw him yesterday.
I only saw him yesterday.
I saw only him yesterday.
I saw him only yesterday.
I saw him yesterday only.
and choose the one that best suits your meaning.
3. He asked me immediately to write the letter.
Clearer: He immediately asked me...; or, He asked me to write the letter immediately.
4. A fine athlete and a good student, her class honored her by electing her president.
Misplaced appositional phrase; her class was not the fine athlete and good student.
Better: Her class honored her, a fine athlete and a good student, by electing her president.
See also Dangling Elements ("da") in this handbook.
For more information on misplaced modifiers, refer to The Fifth Deadly Sin: Misplaced and Dangling Modifiers