Familiarize yourself with the linguistic concept of coordination. Coordination occurs when two or more like elements are joined by a coordinating conjunction. These elements can be words ("cat and dog"), phrases ("out the door and over the fence") or sentences ("He went to the store, and she did the dishes."). When creating compound sentences, be sure each of the coordinated sentences is a complete sentence with a subject and predicate. Occasionally, compound sentences are combined without coordinating conjunctions.
Memorize the coordinating conjunctions. The mnemonic acronym "FANBOYS" is a helpful tool. F = for A = and N = nor B = but O = or Y = yet S = so
Combine two sentences with a coordinating conjunction to form a compound sentence. The individual sentences must be of equal significance. Place a comma before the coordinating conjunction to avoid a run-on sentence.
Examples: The pizza was delicious, and the cake was mediocre. John likes Lisa, but Lisa likes Jack. They won the game, so they will celebrate.
Connect two sentences with just a semicolon when the sentences are closely related.
Examples: He is going to work; he plans to stay until midnight. It snowed all day; the skiing was great.
Coordinate two sentences with a semicolon followed by a conjunctive adverb and a comma.
Examples: He loves reading books; however, he finds magazines a bore. The list of coordinating conjunctions is not too long; in fact, there are only seven.