For google ads, Google uses a quality score to decide which position an ad should be displayed in. Google bases your quality score on your keyword relevance, the quality of your landing page, and how long your page takes to load. Ways to optimize your quality score is to have a good quality click through rate. You can increase it by having your keywords in your ad, both the heading and body. You can add negative keywords and make your landing page relevant to your keywords. Focus on having 4 or less keywords per ad. If your quality score is too low, google may not be showing the ads very often or you may be paying too much per click.
You should set up google analytics and paste the code on your website. Once you do this, you should link it to your adwords campaign so that you can track your advertising better.