Nothing at all is the right answer.
Our government under Theresa May has little or no influence on Trump.
The Labour Party in opposition has been effective in bringing about numerous changes in this governments actions, and when elected, which could be soon, will instigate policies that benefit the many not the few.
Trump hasn't been unable to get many of his policies adopted, but he has managed to create strong opposition, even within his own party.
All this of course is in the USA, and illustrates the point I make about democracy, Trump was elected on a manifesto which he seems unable to secure.
This Cameron government gave the country a choice in the referendum, the Brexiteers offered a policy that promised the electors that the country would leave the EU, the Brexit argument won. If the government can't achieve this then they should go back to the electors, not on a re-run of the referendum, but on a General Election.