As a digital-marketing expert, I often hear skeptics denounce pay-per-click advertising as a solution that doesn't work, has no merit and the whole concept is a dying breed. While there are certainly other advertising strategies flying high (native and social to name a few) it is more important than ever to continue to have a strong pay-per-click advertising plan.

For one, last year, Google switched all searches over to encrypted searches using https servers. What this means is keyword data is not available in Google analytics for organic, non-paid search results. So, there is no way to tell what people are searching for when they land on your website and no way to use that information in your marketing.

With paid advertising this data is still available for site owners and marketers, so they can understand how and which keywords drive traffic to websites and which keyword searches generate results.

Plus, mobile is growing in popularity and pay-per-click advertising will be riding its wave. According to comScore, mobile use will surpass desktop use in 2014 for the first time ever.

Because of these changes, a person’s path to purchase has become more complex than ever. Consumers move from device to device and from network to network.

Related: How to Advertise Your YouTube Videos

So for those ready to bring pay-per-click advertising to their marketing strategy or need some helpful hints on how to maximize their current approach, here are nine mistakes you should avoid in your campaigns.

1. Not doing your homework. It’s important to understand your target audience, their online behavior and what channels they’re active in. This helps you reach your audience where they are with messages they’ll understand.

To get a sense of your audience use keyword research tools. Many of the major search engines offer similar tools, such as the Google Keyword Planner tool. This tool is a free for advertisers, and it allows people to find search volume and competition levels for keyword terms.

Start with keyword terms that would describe your products or services. You can also search keywords for competitors or industry keywords. You will be able to determine based on search volume if your audience is active on that channel.

In addition to the Google, Yahoo and Bing free tools, there are paid options as well. Keyword Spy, SEM Rush and SpyFu are just a few. These paid tools go beyond just search volume and provide more detailed information such as competitor names, competitor keywords, along with average advertising budget and spend.

2. No goal or plan. It is important to set up measurable goals for what you are trying to achieve from your online efforts -- whether it’s sales, leads or branding. A good plan maps out how you’ll get to your goals and makes room for adjustments when you’re off track.

There are paid options available, however, Google Analytics provides extensive data that should fit any advertisers needs for free.

3. No targeting. You need your ads to be specific to location, devices and language. Use available options to target your advertising the right way, so you don’t waste your money on ads that reach the wrong people.

Available options include selecting the language in the advertising settings. Plus, you can choose which devices your advertising shows on, as well as location settings. For example, if you are a local business, you can target a radius around your business, so your advertising only shows to potential customers that fall within that radius.

Related: 5 Pay-Per-Click Mistakes That Can Cost You Money

4. No negative-keyword strategy Negative keywords -- search terms you don’t want your ads to show for -- assist with your return on investment (ROI), as well as acting like an extra security blanket for your ad campaign.

For instance, say you own a women’s apparel boutique and you have many different styles of dresses in stock. However you don’t carry wedding dresses, so you would include wedding as a negative keyword. In the event that someone searches for wedding dresses, your advertisement will not show.

5. No campaign structure. A structure organizes your campaigns into themes, making them easier to measure and manage and keeping your message relevant to your audiences.

As a best practice, you may want to structure your campaigns similar to your website layout by creating a campaign for each of your main categories for products or services. Followed by more specific products or services in your ad groups.

6. Lack of call to action. Not having a clear call to action on your landing page and ads is a common mistake. Test different calls to actions to determine which messages generate the most results. Keep in mind, Google does have restrictions on some call to actions, so stay away from phrases like “click here.” That said, “download now,” “buy now” and “start today” should be fair game.

7. Using the home page as a landing page. When people click on your ad, they should land on a page relevant to the keywords used for that ad. For example, if someone searches for “pink dresses” she should land on a page with several options of pink dresses.

Send them to an irrelevant page, and you increase the chance that they’ll leave your website without taking action.

8. No measurement. If you don’t have a way to measure what you are doing, you’re not going to be able to figure out if your strategy is successful. Most advertising platforms offer a free measurement tool to be able to track results. Use what you learn in your measurements to adjust your campaigns. 

Related: SEO vs. PPC: Knowing Which Is Right for Your Website

9. Lack of testing. When you build your plan you have to test and refine it for best results. Possible changes may be made in target location, time of day, messages, keyword, bidding and landing page, among other elements. Testing all these elements and making changes where needed will make or break the success of a campaign.

One way to do this is use Experiments in Google Analytics, which allows you to test various elements simultaneously. For instance, if you want to test out two or more different landing pages, Google Analytics Experiments allows you to split test to determine the efficacy of each page. 

Related: 10 Questions to Ask When Optimizing Your Website for Mobile Users