How to Use a Dictionary
Pick an entry or two to review. Find the parts of speech and related words, and look up the abbreviations used.
Find several etymologies (word histories) and look up the abbreviations to decipher them.
Check the pronunciations of some words you know to become familiar with the conventions used in your dictionary. Then look up a word that you do not know how to pronounce and see whether you can figure it out.
Note special features such as quotations or examples of use. These are intended to help you find the exact meaning you're seeking. Try substituting the word in a sentence to test it.
Look up abbreviated labels if you need to. These labels can indicate that a word is used in a certain region, for a specific subject, or that it has a special usage such as slang, informal, nonstandard, archaic, obsolete, vulgar and so on.
You can use the dictionary to hunt around for synonyms of words. Although it's not as handy as a thesaurus, you will find plenty of related words by doing multiple lookups using the words in definitions.
For a print dictionary, read the introductory or front matter of the dictionary. You'll understand the various features and how they're set off using typefaces (bold, italic), numbering, lettering and punctuation.
Remember that the dictionary is not an unquestionable authority. It is written by trained professionals reporting on the real use of words and phrases by the general public.