I suggest you take a look at our comprehensive guide on the best keyword research practices here.
In a nutshell, the whole process comes down to these 3 steps:
Generate keyword ideas. If you know seed keywords for your niche, you can easily get tons of relevant keyword ideas. Here are some ways to do it with the help of Ahrefs:
Discover what keywords you and your competitors already rank for in Google search. For this, insert your domain (or any other domain you want to examine) into Ahrefs Site Explorer tool and choose Organic Keywords report from its left menu. You’ll get a comprehensive list of keywords right there.
Also, try the Content Gap section of Ahrefs Site Explorer if you want to see what keywords your competitors are ranking for, but you don’t. Simply insert the desired URLs in the tool and it will generate a list.
Use Ahrefs Keyword Explorer tool to discover a lot of unique keywords you can target. Just insert one or several seed keywords in its search box and get thousands of relevant keyword suggestions.
2. Pick the keywords with the highest potential. When you analyze a list of keywords or browse through keyword suggestions in Keywords Explorer you can apply various filters for different keyword metrics such as search volume, keyword difficulty, traffic potential, clicks, etc. More details on Ahrefs metrics here: https://ahrefs.com/blog/seo-metrics/.
With the help of these metrics and filters, you’ll be able to find keywords with high search volume, but comparatively low difficulty. Besides that, it is a good way to discover long tail keywords, which all together can bring you lots of traffic.
3. Group your keywords and set the priorities. When you’ve collected a huge list of various keywords, it’s time to group them by different factors such as:
parent topic (find which keywords are semantically and contextually related and group them under a “parent topic” to target with a single page);
user intent (to decipher what exactly people want to find when searching for a given keyword, just google it and see what appears first);
business value (establish whether you want to bring visitors to your site, gather backlinks, get conversions or something else and decide which keywords serve your needs best).