I have learnt from my experience of reading (too few than I am supposed to) papers, that the secret to good writing is to expand your cache of verbs. Not to mention the correct usage of prepositions. (I can never tell if I should write secret to good writing or secret for good writing.)
that+verb should be used while introducing a new subject or before a
new clause that requires qualifying a specific action being referred to
a subject. Simply put, use that+verb to qualify an action.
Ex: She admitted that she made a mistake
verb+ing should be used when the subject is already understood.
Ex: He enjoys reading
to+verb indicates the purpose or intention of an action.
Ex: He shouldn’t have joined the army to impress people.
for+verb+ing describes the reason or function of something
Ex: HE is known for singing beautifully
that should be used for restrictive clauses. A restrictive clause is
something that limits the meaning of a noun.
Ex: The song that you performed right before intermission is my favorite.
which should be used for non-restrictive clauses. A non-restrictive
clause simply supplies additional information to the noun.
Ex: These pairs of pants, which no longer fit me, should be given away.