This is a huge topic. I'm giving you my thoughts, and my opinion is distorted by what right wing and left wing are in my country and Europe.

Left-wing is linked to egualitarism, with a focus on poor and vulnerable parts of society.
Right-wing is linked to individualism, with a focus on economic freedom.

I also think that establishment and anti-establishment can take both right or left paths.

The so called end of ideologies is making left and right disappear. New politics would be made by open and closed way of thinking (summarizing an article of Economist).
Progressive left is open, nationalist right is closed.
But, again, you can have nationalist left-wing and liberalish right-wing...