One of the easiest ways of changing sentence structures is to connect them using a coordinating conjunction or a subordinating conjunction.
There are several coordinating conjunctions, but the most important among them are often referred to as FANBOYS. The FANBOYS are:
F – for
A – and
N – nor
B – but
O – or
Y – yet
S – so
Note that when you connect two clauses using a coordinating conjunction, you will get a compound sentence.
Subordinating conjunctions are used to create complex sentences. A complex sentence has at least one main clause and one subordinate clause. The conjunctions commonly used to form complex sentences include the following: though, although, even though, because, since, while, unless, as soon as, after and when.
There is also another category of words called conjunctive adverbs. A conjunctive adverb is not a conjunction in the strict sense of the term. It is not used to join two clauses. It is merely a discourse marker that shows how ideas flow between two sentences. Common conjunctive adverbs are: however, consequently, also, likewise, otherwise, next, then and finally.
Note that a conjunctive adverb should be separated from the rest of the sentence with a comma.
Sometimes prepositions are also used to join clauses. Note that a preposition reduces a clause into a phrase. A preposition is always followed by a noun or a noun phrase. It is not usually followed by a clause.
Here is a list of common prepositions that can be used to connect ideas in sentences: despite, in spite of, due to, owing to, because of, such as, during and upon.