What’s your audience searching for? – Just a few years ago, the average user didn’t trust search engines to understand conversational questions. They were searching with clunky phrases like “flower delivery new york.” Now people feel comfortable typing in things like “who delivers roses near me?” Changes in searcher habits are usually subtle, but will affect which keywords will be most valuable for your site. Instead of focusing on keywords that get you more traffic, focus on those that translate into conversions, revenue, and profits.
The key distinction is that SEM is a broader strategy which combines paid search and SEO tactics. So, if you set up a PPC advertisement, but don't take steps to optimize the ad or the website it links to, this is a standard example of paid search. However, if you optimize your site and your search content with solid keywords, then you put money behind it to boost it on targeted audience's search pages, then you're dabbling in SEM.