Pres. Reagan sought to revive the US in two major ways. One of these was economic and one had to do with foreign policy.
Reagan felt that US economic problems had been caused by big government and high taxes. To try to revive the US, he proposed lower taxes and less spending. He got the lower taxes, but never managed to reduce government spending much. However, the US economy did (for whatever reason) rebound during the '80s.
Second, Reagan felt that the US had been too weak and unassertive in foreign policy. To revive the US, he tried for a more aggressive foreign policy. This included being more confrontational towards the Soviet Union and other communist countries.
In these ways, Reagan tried to fix what he saw as the major problems faced by the US.