What You Need to Know about Keyword Research
Keywords are the phrases or queries people type into Google and other search engines to find the content they're looking for. Keyword Research is used to find those keywords so you can apply them to your SEO efforts. For a successful keyword research strategy, you want to match user intent (what people are searching for) with business value (which keywords bring the right person to your website).
Evaluating a Keyword: Interest and Relevance
The second requirement is relevance. You want keywords that make sense for your business and the content on your website. Ask yourself, if a visitor found my website after typing in a keyword in Google, would it answer the question? Also, would this be a valuable visitor for your business? Would they be the type of person that you want on your website? For example, if you run a website that sells socks, do you want to rank #1 for the term "baseball facts." While that might drive a ton of traffic, are those the type of people that are thinking about buying socks? Maybe later, but there's probably a more impactful set of keywords for you to target.
Think of keywords like questions. People who type them into Google are looking for an answer. Is there enough interest in this question for you to target it with your website? And is this question relevant to the purpose of your site? Once you understand this theory you can begin evaluating keywords.
Picking the Best Keyword Opportunities
Take the terms you've gathered and note the amount of searches they get to gauge level of interest. Then evaluate them in your mind by the idea of relevance. You can give them a score of 1-3, 3 being most relevant and 1 being least relevant. Order from highest too lowest, terms that have the highest interest (most searches) and highest relevance (most important for your business) should be at the top.
Once you have the list ordered take another pass with an eye for balance. If the top keyword is searched over a million times a month, it might be too competitive. Soon you'll have a list of starter keywords to look at that can help decide which elements of basic SEO tools you want to go after. Also, look at the search results pages where the keywords are, do they have a lot of competition? See if you can provide better content on those pages and then attack those searches. It's a blend of opportunity and what you can realistically achieve on your site. There might be some keywords you hold on for later if you're just starting because your site will only grow in strength as time goes on. If you already have a Google Search Console setup it's also good to look at keywords that you already rank for and are already driving traffic. This will show potential opportunities to optimize your pages further and these can become some of your lead first level keyword targets.
Keyword research never stops, and should be a consistent monthly activity for your site as you look at initial keywords and then evaluate performance and interest over time.