Quick question… in your review you mentioned focusing on some products like ProductNamethat are spelled as Product Name and are low competition. My question is how would you tackle a review using a keyword like that? Would you make that the primary one that is misspelled? Would you mix them with the spaced spelling and correct spelling? I’ve found some good ones and would appreciate some direction on how you’d handle writing a post to rank for the spaced keyword?
Trying to rank for the keyword “Best Headphones” will see your post, page, or article buried in the depths of a billion search engine pages, and it’s never going to surface in the top thousand pages, let alone page one…ever! But going for a keyword, or Long Tail keyword phrase “What are the Best Headphones for Sleeping” will stand you in better shape to get somewhere close, or even on, the first page.
Note: If you can’t justify using Ahrefs on a monthly basis, you could sign up for a month, do your KW research and cancel. That said, if you can justify the monthly pricing it’s well worth keeping because you’ll get access to the ongoing functionality such as rank tracking and web monitoring. It also means there’s no need to use any other tools to track rankings or monitor mentions on the web.
Keyword Researcher is designed to search the Autocomplete databases of Google, YouTube, and even Amazon.com. That's a lot of keyword sources! As you probably know, if you're building an authority site, or if you would like to become a dominant player in your niche, then starting with a large database of keywords (that your customers are actually typing in) is a powerful marketing tool.
Google has introduced Google Suggest in 2012. Google Suggest is typically used as a live feature while a user is typing a search phrase into the browser or google website. Google Suggest uses the organic search input of billions of users and try to "guess" that way what a user might be searching for even before he completed entering the query or all the words of a keyword phrase.
2) SpyFu: I suggest to have paid account on SpyFu. I just need to find my competitors who using Adwords and review them using this tool. It will show me what ads and keywords they are using. Note that my competitor who paid for that particular keyword knows exactly that it is important for his business including recent trends. Also using SEO feature you can input any URL and find our which keywords they are ranking for.

How do I research keywords? This is a common question I get from clients. And my immediate response is… Long Tail Pro! With the update to Google Adwords Keyword Planner (rendering it near worthless) without paying for Google ads and to test actually search volume for keywords, the generic Avg. search volume range they provide gives you ZERO actionable data! See example below:
"I rarely get excited about SEO and SEM tools...But, when it comes to keyword research it is virtually impossible to produce a quality worksheet without software. When I have to perform the same task for my customers, the process is even more daunting and time consuming...there is now a better way to manage huge keyword lists and this tool is called WordStream."
Long Tail Pro is a keyword research tool. Keyword research helps you find exact keywords that people are actually searching for. Some keywords are high competition (meaning it is harder to rank for on your site) and some have lower competition (easier for you to rank). How does Long Tail Pro work? First it finds the actual keywords for you based on the ‘seed keywords’ that you input. Then it helps you analyze the competition to see which keywords will be harder or easier for you to rank. How does this benefit you? You can take those ‘easier to rank’ keywords and use them in your content to increase search engine traffic to your site.

The objective of keyword research is to generate, with good precision and recall, large number of terms that are highly relevant yet non-obvious to the given input keyword.[2] Process of keyword research involves brainstorming and the use of keyword research tools. To achieve the best SEO results, it is important to optimize a website as well as backlinks for the most relevant keywords. It is good practice to search for related keywords that have low competition and still a high number of searches. This makes it easier to achieve a higher rank in search engines which usually results in higher web traffic. The downside of this practice is that the website is optimized for alternative keywords instead of the main keyword; main keywords might be very difficult to rank for due to high competition.[3] There are three essential concepts to consider when conducting keyword research. Good keywords are closely related to the subject of the website. Most search engines use an internal quality system to check website relevance related to possible keywords, a non relevant keyword is unlikely to rank well for a website.[4] Good Keyword that are highly competitive are less likely to rank in the top. Keywords that have no monthly searches generate no traffic and therefore are useless for SEO. Keyword stuffing in a web page should be avoided.
The Search Based Keyword Tool is intended for researching keywords within Google’s Adwords network. Unlike the Keyword Tool, the Search based Keyword Tool is based solely on searches from Google.com. This factor causes the search volumes displayed to be considerably lower than the Keyword Tool. Because this tool is intended for paid search keyword research, it contains additional information on Suggested Bid and Ad/Search Share. The Search Based Keyword Tool is seamlessly integrated into the Google Adwords interface and allows marketers to add keywords to their PPC campaigns without having to login to their Adwords Client Center.
It would be great if you can provide comparative analysis of this tool with Google Keyword Planner. Since you’re using this tool so you can provide best comparison. One differentiation which I understood is that this tool works for yahoo and bing as well whereas Google keyword planner works only for Google but Google being a dominating search engine, gives the highest returns, so only this reason may not be enough to buy it.