Paste some of your Keywords in keywordtool.io and find more combinations and long tail possibilities
You can also use Keywordtool.io to find question type search phrases (English language only)
Search for Q&A terms via Google Keyword Planner
When carrying out keyword research, look for questions that you will be able to answer in great depth. The Google Keyword Planner can be used to find a range of queries relevant to your industry—simply pick out your product category and include keywords such as “how”, “why,” and “where”.
Reverse lookup with Google Keyword Planner
Search for one or more of your target keywords in Google, and note down a high-ranking page's URL.
Set it as 'your landing page' in Google Keyword Planner to see the keywords it is ranking for as well as suggested terms.
Search in Quora
Using the same seed as you chose for UberSuggest, search in Quora to find questions real people have about your topic. Add new keywords and phrases to your sheet.
Repeat this for other derivative keywords if you like.
Get keywords from the Wikipedia article
Wikipedia is perfect for well-written content that explains concepts in terms people understand and search for.
Go to Wikipedia and search the topic of your page.
Quality related keywords will be both in the text and as suggested categories. For example:
Add these categories and keywords as new entries to your sheet, and see if you can create new keywords by combining them with existing entries.
BoardReader scrapes a huge network of forums for conversations matching your keyword. Search your keyword in BoardReader and get ideas for quality keywords people will search for.
Add the keywords to your sheet.
Reverse lookup with Positions Explorer
The SEMRush software offers a powerful way to get competitor information.
Using the same competitors as in the task above, search a competitor's URL in the Explorer to get a list of keywords like this:
Add any relevant keywords to your sheet, repeat as many times as you feel is necessary, then go to the next step.
Remove duplicate keywords
Since we’re working inside Sheets, this is easily done with the Remove Duplicates addon. Install that, then go to the Add-ons menu in Sheets and select the 'Remove Duplicates' section.
Press 'Next' the whole way through, then 'Finish'.
Copy remaining keywords into Google Keyword Planner
The fastest way to narrow down your keywords further is to get rid of the ones that don't have any search volume.
Get all your keywords out of Sheets, then paste them into Google Keyword Planner, like this:
Once the keywords are in Google Keyword Planner, hit Download as shown above.
Tidy up the downloaded sheet and merge it with your original
Open your downloaded Google Keyword Planner sheet or sheets.
Delete everything apart from the Keyword, Volume and Competition columns, then paste it back. If there’s no volume data, then don’t bother. Those keywords aren’t popular enough and that really helps us narrow down our list.
Remove the keywords that don't make sense
You are certain to get a lot of keywords from automatic generators that are not grammatically correct. Also there will be keywords that are not relevant to your brand's product that you are targeting.
Remove keywords that don't make sense in a sentence. For example, 'network security how to' and 'network security basics youtube'.
Remove keywords that are branded. For example, 'apple network security' or 'microsoft network security'.
Remove non-evergreen keywords. For example, 'network security best practices 2012'.
Remove irrelevant keywords
If you're writing a post about network security tools, then having 'network security best practices' isn't 100% relevant.
Get rid of anything which doesn't accurately describe the page you're optimizing.
Filter by search volume
Your list undoubtedly contains several highly competitive search terms which we wouldn't have a shot at ranking for, so by filtering by search volume, we can gloss over these and get to the slightly less competitive, but most effective keywords.
In Google Sheets, click the small arrow that appears when you hover over Column B's header (the cell where it says 'Volume' and go 'Sort sheet Z-A'.
There you'll see the more reasonable options at a glance, which I highlighted in the picture below:
Consider removing highly competitive keywords
A big part of deciding if a keyword is worth targeting is looking who is already ranking for that term.
If you find that hugely popular and authoritative sites are ranking for your target term, you're in for a tough time.
Use the first spreadsheet you created with all your research in to finalize a target set of keywords that can be referred to when you start to write content on your target landing pages, blog posts or other web page content formats.