What exactly does someone do to behave like a politician 
If you were politician whose goals were like many of their ilk, you'd do and say whatever it takes to get elected or reelected. One of the main things folks promoting someone who is inspired or coerced into being elected to or retain a political office does is figure out what inspires the majority of the voters to actually vote for a candidate and develop a campaign which will hopefully result in them being elected. Without spelling it out in too much detail, a candidate or an incumbent panders to their base and their financial support.
Given the above, most successful politicians are ultimate diplomats. They tightrope walk a thin, tenuous and ever changing line that sways between political ideologies. There are also renegade politicians who tap into a resistance to the status quo, Trump being a great example of this. Like it or not, he was elected because he challenged the norms and promised change, (empty the swamp). He appealed to those of us who feel disenfranchised with government as it is and feel helpless to change it.
Unfortunately for Trump, he is not a politician or a diplomat. He's bucking a time worn system and doing it with a total lack of finesse. The cards are stacked against him. Rebels love what he's doing, but ultimately he will fail them. Change is historically gradual. A politician is diametrically the opposite of Trump. He's an underdog and we love and cheer for underdogs, but underdogs rarely win.
