Pay-per-click (PPC) marketing can be a powerful tool to boost traffic to your website for a relatively small investment. It allows you to "jump the queue" and make sure you get seen by the audience you want to target. On mobile, where most organic results appear "below the fold," it can mean the difference between making the sale and not even popping up on a user's screen.

PPC programs offer a broad range of powerful techniques to help you pick out which users you want to target but, as they say, with great power comes great responsibility. Here are some common mistakes you should avoid.

1. Spending too little

When you're looking at budgeting for a campaign, everyone worries about spending too much. However, spending too little can be just as risky. You definitely need to pace yourself when it comes to budgeting, but you also need to learn if what you're doing is actually working. You can't make those decisions without data, and you can't get data if you're not willing to spend enough money to give your campaign a fair shot.

2. Being too general

It's tempting to chase the most popular keywords and queries in an effort to make sure that the money you're spending gets you in front of as many eyes as possible. What's important to remember is that it's not just a numbers game. You need to consider fit as well. The digital landscape is filled with niches. It's okay to go after something that's not searched as frequently if you're sure that you'll be a perfect match for the people that are looking for it.

3. Trying to test too much

One of the best things about a PPC ad is that you can test and tweak it as you go along. Most PPC programs will give you reams of data and many different ways to look at it. The important thing to remember is that you need to take a scientific approach to iterating your campaign. If you don't control your variables, you wind up not learning anything from your experiments. As you work to find the right adjustments, make sure that you're not changing too many things from iteration to iteration. Focus on one thing at a time, and you'll be able to tell what's working and what's not.

4. Using keywords incorrectly

Keywords are at the core of building a PPC campaign, but you should make sure that you have clarity about which keywords go with which ad groups. If you have too many broad-match keywords, you'll get a lot of searches that just aren't relevant and don't have a prayer of drawing a click, let alone a conversion. Instead, focus on phrase match keywords that help you get specific about who you're trying to reach and why they might be looking for you.

The amount of raw data you can use to tweak your PPC campaign can be overwhelming, so you need to be specific. Focus on who your target audience is, be methodical about testing your campaigns, and make sure that you spend enough to actually learn something, and you can build a campaign that works for you.