In his excellent 1945 essay "Politics and the English Language" George Orwell lays out six rules of what not to do when writing. Every aspiring writer should be obliged to consider Orwell's excellent advice.
1. Never use a metaphor, simile, or other figure of speech which you are used to seeing in print.
2. Never use a long word where a short one will do.
3. If it is possible to cut a word out, always cut it out.
4. Never use the passive where you can use the active.
5. Never use a foreign phrase, a scientific word, or a jargon word if you can think of an everyday English equivalent.
6. Break any of these rules sooner than say anything outright barbarous.
According to Orwell, along with the key points he posited (in part one), he informs us that these are the most elementary rules one can follow when trying to write clearly and get one's meaning across as straight foreword and efficiently as possible. It's good advice for any writer, and one which I personally aspire to.