How did Great Britain combat Napoleon Bonaparte's naval blackade?

I assume that you are talking about the policy of Napoleon
that is known as the "Continental System" or the "Continental Blockade."  Napoleon did
not have the naval resources to mount a naval blockade (where his ships would intercept
British ships).  Instead, he tried to enforce the blocakde by ground-based efforts.  In
other words, he tried to get the governments of the various continental countries to
prevent trade with Britain from happening.

Unfortunately
for Napoleon, the continental countries benefitted from trade with Britain.  For this
reason, they were not all that energetic about trying to enforce the blockade.  This
meant that smugglers were able to carry goods to and from Britain.  The blockade did
hurt Britain to some extent, but it was ultimately unsuccessful.