How do I find out which is most popular keywords in google?
Possible Keywords,
1 - London Business
2 - Online Business London
Then I need to make a decision for URL friendly (SEO), example:
/london-business
/online-business-london
/online-business/london
Try using the Google Adwords Keyword tool: https://adwords.google.com/select/KeywordToolExternal
this will give you the related keywords, the Global Monthly searches, relevance, etc. Then compare the metrics for each keyword.
Now '/online-business-london' is probably more SEO friendly than the other options. And a more specific set of keywords is preferred than a general one because you will be targeting people that are interested in 'online business' rather than 'business' in general.