GNUSMAS I am also not a teacher, but as chief_chaman478 pointed out, you have far too many reactors, and they are too far away from the weapons. For a 500k ship, it's definitely on the weaker side.
But the biggest thing you're lacking is compartmentalization.
Here's an example 500k ship, (it's less than 1,000 credits more than your design).
As you can see, the reactors are much closer to the weapons, and, crucially enough, the ship is split into compartments, allowing the crew to operate in small groups, separate from the rest of the ship.
Here is a link to one of the best guides for ship building that was mentioned previously: https://forum.cosmoteer.net/d/7783-cosmoteer-ultimate-ship-design-and-part-guide
Use this to help familiarize yourself with some of the game's features! Cosmoteer has some interesting features and design choices that may seem counter-intuitive, so the above guide should help you start making better ships in no time!
EDiT: Figured I'd post my only other ship that was specifically designed to be at 500k:
Note, its rather prone to exploding, and overall was not what I had hoped it would be (To be fair, the first design I posted is also sort of weak). Try improving your ship so that you can beat it, as a test!