This deserves a book-lengh answer, and in fact if you want a good history of this, N.A.M. Rodger would be your go-to source (start with The Wooden World and continue with The Safeguard of the Sea and The Command of the Ocean). Also, Britain was a constitutional monarchy, but certainly not a democracy. And "Britain" became a thing after the Act of Union in 1707, but the foundations of British naval power can be traced back at least to Tudor times.

Anyhow, since I don't feel like typing up a book, could I suggest you read this answer I gave on the same topic before:

http://www.reddit.com/r/AskHistorians/comments/2nydmp/how_did_the_british_navy_remain_dominant_for_such/

and maybe these posts which expand on a few of those topics:

http://www.reddit.com/r/AskHistorians/comments/2fs8qr/how_much_more_advanced_was_a_british/

http://www.reddit.com/r/AskHistorians/comments/29f3s7/how_does_the_royal_navys_organisation_command/

http://www.reddit.com/r/AskHistorians/comments/2709jm/how_would_a_britishhms_frigate_built_in_1715/

http://www.reddit.com/r/AskHistorians/comments/26gzlj/was_it_possible_for_a_age_of_sail_navy_ship_to/

http://www.reddit.com/r/AskHistorians/comments/38sjil/how_did_britain_manage_the_logistics_of_fighting/

http://www.reddit.com/r/AskHistorians/comments/25nush/how_common_was_it_for_the_royal_navy_to_send/chjilgb

and maybe get back to me with questions? I'm traveling for the next couple of days but I can respond to follow-ups after that. But that might get you started.

You can also find some other posts of a similar nature on my profile page: http://www.reddit.com/r/AskHistorians/wiki/profiles/jschooltiger

And please ask questions or let me know if this is helpful.