When we want to indicate in writing that someone is talking we enclose what they say in speech marks: "This is all I have to say!"
We normally include the name of the person speaking with the speech:
Punctuation must be enclosed within the speech marks, not outside:
Right: "This parrot is dead," said the customer.
When writing conversations, a new paragraph is begun each time a different person speaks:
"Is your beard made of cream like ours?" said the cow.
Instead of using said to denote speech, use a variety of alternative words (as long as they are appropriate) such as:
cried, explained, shouted, whispered, announced
Break larger amounts of speech up into smaller chunks by pausing to desribe what is happening, before continuing:
"I just can't get this lightbulb out of its fitting!" screamed Alastair, reaching for a hammer, "I wish we'd bought energy efficient ones."
Whatever you do with speech, keep it flowing so you don't lose the reader's interest. You've read this far, haven't you?