Undercut the back side of the front sight, so that no light reflects back to your eye. Use a file.
If you want different colored front sights, they are available from suppliers. They cost, but they are available.
I like the kind that have a colored plastic insert in a tube, with a port cut in the tube to let in light.
They now come in very small diameters, so you have a fine "point " of light to use as a reference for your front sight. With daylight coming into the tube through the port, the end of the plastic facing you "glows", and is highly visible in the lowest of light conditions. I like "green", personally, for its use in a wide variety of light conditions, for what my opinion is worth.