Reaching people at the right time with the right message requires some forethought. Here's a guide to getting started.

Keywords are the key to a successful search marketing campaign. Pick correctly and your ad will show up at the perfect moment, when a user is ready to learn more and is interested in what you have to offer. But how do you figure out which keywords are the right ones? Here are ten quick tips to get you started.

1. Be thorough
Search engine users don't just search specifically for your most popular products, or the ones that are currently on sale. As a result, your keyword list shouldn't focus exclusively on those words either. Make sure that every single offering on your site is represented within your keyword list so that users can find what they're really looking for.

2. Be descriptive
Users treat the search engines like giant Consumer Reports databases. They don't just search for "dishwasher," they search for "best dishwasher," "top-rated dishwasher," etc. Although many marketers shy away from including words like "cheapest," "low-price" or "discount" in their other marketing efforts they can be incredibly effective at reaching customers researching their options. Furthermore, those offering content should consider adding the word "free" to their keyword list (as in "free recipe" or "free diet tips").

3. Misspellings
Many marketers never realize the opportunity misspellings provide. While most engines do a good job of catching misspellings, and pointing users in the right direction, few advertisers do the same. By targeting common misspellings of the most popular (and hardest to spell) words from your list, you can reach interested people in an environment where few of your competitors are represented.

4. Know your audience
We once worked with an auto manufacturer who refused to buy keywords that referred to the company's product as anything other than a "vehicle." What was the problem with that? A vast majority of the company's audience was searching for "cars." Know your audience and the vocabulary that those who comprise it use, and make sure to factor that in to your keyword development.

5. Use all available resources
One good way to know the way your audience thinks about your products is to look at the way they interact with your site. By scanning your site's search logs, referral logs and customer service emails you can see the keywords users already use to find and navigate your content. Additionally, take a trip over to your competitor's site and find out the words and phrases it uses to describe similar products.

6. Use multi-word phrases
The number of words per search has been steadily rising over the past few years. Rather than targeting single terms, combine words into phrases. What the resulting phrases lose in total number of searches they make up for in vastly increased relevancy. As a bonus, run these phrases together into a single term, without any spaces ("diettips" instead of "diet tips," for example). Many users are beginning to navigate the web through URLs that don't have spaces. As a result these longer terms often get more traffic than you'd expect.

7. Get specific
Don't fall into the trap of thinking that "no one will ever search for that." Search behavior is varied and broad. Therefore, you shouldn't be afraid to use specific model numbers, detailed product names or other small aspects of your products as keywords. Chances are that someone, somewhere will be searching for it.

8. Study your own marketing
It's also important to consider the ways users interact with your brand when they're away from their keyboard. Your marketing efforts in other media hopefully generate interest in your products. And when people are interested in something, they turn to search engines. Consider incorporating the words, phrases and themes from your commercials into your keyword list -- assuming that you have content on your site to back them up.

9. Be negative
All major engines allow something called "negative matching" -- essentially, it helps you weed out irrelevant traffic by specifying instances in which your keyword may appear in a search that isn't related to your business. For example, if you were bidding on the word "Lincoln," you could ask the engines not to show your ad if someone searches for "Abraham Lincoln" or "Lincoln, Nebraska." Think of all the possible ways that your keywords might appear in searches.

10. Test everything
One of the most powerful aspects of search marketing is the fact that you only pay when people click on an ad. Furthermore, they likely will only click if the ad seems to be relevant to what they were looking for. Because virtually every click from a search engine is a "good click," the most costly aspect of building a keyword list is the time it takes to build and launch it.

Joshua Stylman is managing partner, Reprise Media. Read full bio.