Like any president, Trump is taking credit for good economic news. his highlighted rising stocks and falling unemployment. But Trump also, famously, regards trade deficits as a sign of economic weakness.
he's doing better than his opponents will admit and worse than his supporters believe.
I doubt that rising stocks are particularly related to Trump´s policy. The main predictor
for stock market movements are the interest rates from the most important central
banks of the world (of course the Federal Reserve is the most important one).
Low interest rates lead to a huge influx of cheap money into the markets, which
causes a rise in all asset classes (stock market, real estate...).
Besides, the big central banks have been buying bonds in order to prop up
the market in violation of their actual mandate.
All in all the markets are propped up by the unprecedented amounts of liquidity
that have entered the markets due to the central banks policy. Obviously,
Trump is claiming that this was his success, but without these measures we wouldn´t have
seen so many good economic news.