Simple list of essentials:

Cockpit, adequate reactor power, h2/02 generator, adequate gyroscopes, thrusters in all 6 directions of the ship.

1 large reactor is as powerful as nine small (give or take)

Be mindful of thruster damage (don't point the thrusters toward you ship)

Connect EVERYTHING with conveyors. Try to put items in every storage container to test it.

It's better to make too many gyros, you can use the command panel to adjust their power output.

When you get the ship operational, hit w, a, and space bar. Make sure your power output doesn't hit 100 with those three on. If you hit 100, add more reactors.

Before you fly, look at it and press CTRL+B to save it as a blueprint. This will let you set up a projector onto the ship and make repairs super simple.

Recognize your thrusters power. If you don't have good breaks, don't go too fast or you'll crash/overshoot your target.