One of the best manuals on writing better is Strunk and White’s “The Elements of Style”. Here’s a taster:
“Omit needless words
Vigorous writing is concise. A sentence should contain no unnecessary words, a paragraph no unnecessary sentences…This requires not that the writer make all sentences short, or avoid all detail and treat all subjects only in outline, but that every word tell.
Many expressions in common use violate this principle.
the question as to whether = whether
there is no doubt but that = no doubt
used for fuel purposes = used for fuel
he is a man who = he
in a hasty manner = hastily
this is a subject that = this subject…”