What's the best way to find out what keywords a website is ranked for?

Usually the source page can list all the keywords but that is not always a feasible way to do things since many tools exist to get this job done quickly and efficiently, tools such as Google AdWords, Open Site Explorer, SEMRush, Alexa and Spy Fu are some of the tools that are great at getting the job done, Word tracker is also one of the very old and reliable ones.

I hope this question regarding Which Keyword is best (Listed top on search engine)_ on your own web site. You can get details about keywords from Google Web master tools just integrate web master tools on your website and you get details reports regarding all keywords.

 Well, it must depend on your topic. But there are many tools in the market which give you the result according to your topic, simply try to do some searches on the google and there are many tools which helped you a lot like,

1- ahref

2-scrapbox

3- kwfinder

4-semrush

5- longtailpro

You need to find the keywords first. List them down and sorted it according to the searches and competition. There are multiple free tools available in the market. Once you have the selected keywords you need to check your website ranking on your selected keywords. 

If you have any questions/confusion don't hesitate to contact me.

Thanks

We can use bellow listed tool for tracking rank of websites for the keywords. These tools will help you for finding keywords of the websites those are ranked in websites. 

Open Site Explorer

Ahrefs Alerts

Positions Explorer

Content Explorer

Position Tracker

Crawl Report

Position Tracker

Crawl Report

If you are the owner of the website you can find these keywords in Google Webmaster Tools and Google Analytics

Keyword should not be auto-translated. They must be localized. Brainstorm with your team, think your self and ask your team to suggest relevant keywords. You may want to try also Google suggest keyword related searches. Make sure to find Long Tail Keyword with Low SEO competition.

it depends on framework you are using.

there any many tools to check but that consumes alot bandwidth and computer speed.

you should use online tools for that. and "Rank Tracker by SEO powersuit" "WP Rankie" for wordpress site

Whatismyserp.com for keyword ranking in google all locations