My experience with Blokus is that it pays to not be confrontational. If the board splits into two 1v1 games, and players A and B are being confrontational and denying each other access wherever possible, and players C and D are being semi-cooperative and leaving gaps to work around each other, then players C and D will naturally get more of their pieces onto the board. If there's a region you've trapped all the other players out of, then you'll only be able to take advantage of about half the space. Whereas a region twice the size, shared between two players, can let both those players get twice as many of their pieces down, if they leave space for them.
So while I've encountered people using the Barasona opening, I don't use it myself. I find it pays far better to have fingers in as many pies (areas of the board) as possible, and not care who has fingers in my pies.
To this end, I try to run straight for the centre, and then extend tendrils towards any zones that are looking particularly contested. Specifically I'll start with (in some order) Z, V, W; sometimes amended to insert the X, which I often find hard to shift later on.
I also aim to have my first 12 plays be the 12 pentominoes. This often isn't possible - I'll want to get a finger into an area that needs me to use the 4-square line or some such - but when I do manage it, it leaves me very well set up for the late game.