There's different aspects he may have some impact on or none at all providing he actually tries to do what he campaigned on.
Politically he says he wants to end lobbyists influencing politicians. Given that most representatives fund their campaigns and lives from taking lobbyists money then he'll get no support from either side on that. Not to mention that once he's not president he'll be back to lobbying as well.
2. There's not going to be a wall. He could and should stimulate economic growth by embarking on large infrastructure projects but given how much needs to be put into the road, rail and water infrastructure he'd probably be best to do that.
3. Trade. He'll be a disaster. His cutting corporation taxes to try and get US companies to stay in the US coupled with saying foreign companies with have to pay substantial levies to sell to the US means countries will stop selling to or buying from America. China dominates raw materials needed for much of the US manufacturing. They'll simply add their own tariffs like they've done in the past so US companies can't compete.
4. Foreign relations. It'll be a mixed bag. He'll have strong relationships with the UK (Well parts of it), Israel, France after they inevitably elect Marine Le Pen, Russia but probably not the rest of Europe or any southern American countries.
5. Middle East/Islamic terrorism. Probably a disaster. His Instinct is to send in troops. You end up with more destabilised countries probably including Pakistan and possibly turkey and Jordan plus a few more African countries.
6. The environment. Totally ****ed. His presidency will encompass the tipping point of heading towards +5 degree Celsius increases by the end of the century. The Paris treaty was literally the last chance. Even with it fully ratified the 2 degree increase target is already gone. His plan is to renege entirely on the Paris treaty and to hugely increase the extraction and burning of fossil fuels.