Know Your Conjunctions
When you're writing, you want the reader to perceive your ideas in the same way you think of them. To do so, you need to show the connections that exist between the ideas in your mind. Here's a list of coordinating and subordinating conjunctions and introductory adverbs you can use to indicate certain relationships.

RELATIONSHIP	COORDINATORS	SUBORDINATORS	INTRODUCTORY ADVERBS
addition	and		moreover, also, further, furthermore, additionally, what's more
contrast/opposition	but, yet	although, though, while, even though, even if, whereas	however, nevertheless, on the other hand
cause	for	because, since, as
result/effect	so	so that, in order that, in that	therefore, thus, hence
choice/opinion/alternative	or, nor		alternatively, on the other hand
condition		if, unless, provided [that]
time		after, as soon as, before, since, until, when, as	then, next, afterward, subsequently, earlier, previously

How to Use Conjunctions

• Coordinators and subordinators join sentences; introductory adverbs, or transition words, do not.
• Although coordinators can introduce complete sentences, they then have the force of an introductory adverb, since technically you violate a grammatical rule when you begin a sentence with a coordinator. Should you do so, don't follow it arbitrarily with a comma.
• Subordinators can begin sentences, but since they begin dependent clauses, make sure you have an independent clause following the dependent one; otherwise, you'll have created a fragment.
• To test whether a word is a subordinator or an introductory adverb, see whether you can move the word without affecting meaning; if you can move it, it's an adverb.

Basic Punctuation Patterns
Here are the tried-and-true patterns for structuring your ideas in sentences, along with their punctuation.

Independent Clause, Coordinator Independent Clause.
Adverbial Clause, Independent Clause.
Independent Clause Adverbial Clause.
Independent Clause; Introductory Adverb, Independent Clause.
Independent Clause; Subject, Introductory Adverb, Verb Phrase.
Independent Clause; Independent Clause, Introductory Adverb.