Do more for the poor.
It's really that simple.
Netherlands had a right wing government. They messed up greatly. People voted even more right because "obviously" the previous government was actually left wing.
Perception matters a lot for a large group of people.
And it's funny because when certain parties make promises there interpretation differs depending if they like the party or not.
E.g. making promises to improve things: who will pay for it? E.g. left wing is spending money they don't have, or they care too much about lazy people.
If a right wing party makes a promise to improve things and financially it is pretty much certain it'll not work out: don't be negative, just saying that because of x/y/z.
It's too easy to blame left wing parties for what is happening. Pretty sure there's various causes, and people often aren't logical or rational.
They say migrants, but mean asylum seekers. While actively encouraging as much as possible foreign workers for e.g. ASML. Asylum seekers only make up a tiny portion of the migrants. Knowledge workers however, ...
Far right thrives on stuff like this.