Latin is taught in many high schools and universities, chances are you will be able to locate a student in your area who speaks Latin, and will be able to help you with your grammar.
Make a list of essential Latin grammar rules, or purchase a grammar chart like SparkCharts Latin Grammar (a handy laminated grammar chart available at Barnes & Noble, Borders or on Amazon.com for about $13). Practice daily.
Purchase a comprehensive study guide to learning Latin. Wheelock's Latin (which has been the reference standard to learning Latin since it was published in 1956) is available online or in major bookshops like Barnes & Noble for under $30. The book also has a handy workbook which can also be purchased, so that you are able to record the answers to your exercises and practice memorizing important grammatical rules.
Peruse other alternatives. Aside from learning with books and a tutor, computer software for learning Latin is available as well (Rosetta Stone makes one of the best Latin programs available, breaking your Latin lessons into three courses--comprehensive to expert, but it is pricey at about $250 per set). If money is not an object, Rosetta Stone is an attractive choice and can be very helpful in teaching you to learn Latin grammar quickly and correctly.