There are different kinds of sentences. Varying sentence type and length makes your writing more interesting.

A simple sentence contains a subject and a verb. It expresses a complete though.
Josh plays rugby every morning.

A compound sentence contains two independent clauses joined by a coordinating conjunction (and, but, for, not, or, so, yet).

Josh plays rugby every morning but Steven only plays rugby in the afternoons.

A complex sentence combines an independent clause with one or more dependant conjunctions (after, although, because, since, when) or a relative pronoun (that, which, who).

I don’t see Josh in the mornings because that is when he plays rugby.

Too many simple sentences can make your writing seem … simple.

Easter is a nice holiday. You get to spend time with your family. You get to eat chocolate. You shouldn’t eat too much chocolate. Chocolate isn’t a health food. Family is important.

Each of these short sentences should/could be either combined or extrapolated to give the writing depth. Short sentences could then be used effectively to highlight key points or to stress an idea in creative writing.

Easter is a nice holiday because you get to spend time with your family. You get to eat chocolate but you shouldn’t eat too much. Chocolate isn’t a health food but there are many other great foods you can eat at Easter. Making a roast dinner or an Autumnal salad would be a relaxing and healthy way to spend time with your family. The key joy of holiday times is being with family.

Creating Compound sentences

Turn each simple sentence below into a compound sentence.
1 We ate lunch, and then we went to the park.
2 The rocket flew high but exploded in the air.
3 Emily sang a song, but her voice was all cracked.
4 The goldfish swims in the pond, but he has no friends
5 The party was fun, so I had a great time.
6 On Wednesday Peter put his hand up in class, but the teacher ignored him.
7 Bert likes fruit for breakfast., but this morning he had toast.
8 What is your favourite colour? the teacher asked the children.