When your sixth-grade English teacher was droning about gerunds and diagramming sentences, you probably thought "Why does this stuff matter?" By now, you know it matters a lot. Good grammar helps you speak and write more clearly, and can be the determining factor in earning high grades or snagging your dream job. With so much riding on the way you speak and write, why not ask yourself: What is a gerund, anyway?
Purchase a grammar workbook from your local bookstore. These books often include a self-assessment test, which will help you identify your grammatical areas of weakness. Working through the related exercises is a good way to start improving your skills.
Sign up for a grammar refresher course through a local college or adult education program. These programs - often geared toward business professionals - will review the grammar rules you forgot after sixth grade and point out the most common grammar mistakes.
Read. People who understand grammar can usually tell when something sounds "wrong" without thinking about the rules. Reading will help you pick up that skill by exposing you to proper usage of the English language.
Be vigilant. It takes a lot of practice to acquire good grammar habits. Use correct grammar in every situation, even the most casual email or text message to a friend. Never send a message without proofreading it, and keep grammar books nearby to look things up when you're unsure. It sounds like a lot of work, but before long you'll be using proper grammar automatically.
Before you pay tuition for a grammar refresher course, check your employer's policy on continuing education. Some companies will reimburse employees for job-related course work. If you know someone with excellent grammar skills, ask him for help. He may be willing to "grade" you periodically by reviewing a document or email you have written.
Don't agonize about every mistake. Learning good grammar habits takes time.