Keep your sentences simple and clear. Don't use to many complicated sentences.
Don't make all the sentences the same length. It is a good idea to vary the length of the sentences. Make some sentences longer, while keeping some sentences shorter.
It is better to use the active voice, than the passive voice.
Don't use abbreviations unless you are sure that the reader will understand.
It is better to use nouns and verbs, instead of adjectives and adverbs.
Keep your descriptions short and simple. Keep your writing short and to the point.
Use words that the reader is familiar with. Don't use words that the reader might find difficult to understand.