One of the most common mistakes seen in dialogue is that the end of the dialogue is the end of the sentence, e.g - "This is a terrible meal." He said.
Even in professionally published novels sometimes these mistakes are seen, the best way to view correct examples are to look within prolific writers novels to see how they are properly written, writers such as Stephen King, Elmore Leonard, etc, who use editors are the best to use for examples, writers such as Anne Rice who do not use editors and there fore have too many unchecked mistakes are not good examples to follow.
Professional editors and authors agree that dialogue tags should be invisible to the reader in the text so they don't distract or detract from story. Invisible dialogue tags use simple verbs. It's generally accepted and recommended that two verbs are preferred: said and asked.
Dialogue tags aid in mimicking speech patterns. Pages of dense, dialogue-only paragraphs do not capture the rhythms of actual speech. Few people talk in lengthy monologues. On the other hand, stories can rarely survive attempts to capture every hesitation, stutter, restart, and mindless bit of chit-chat heard in common conversation. Because of this, dialogue tags are just the bits to put space in speeches and make them feel real without derailing a story. Simply put, when dialogue has tags, it has rhythm, and the reader experiences pauses just like in actual conversation. It's also important to consider