I always thought the distinctive design of the old F-19 Stealth Fighter kit would make it a tough base for a spaceship. Generally, I turn the beginning form upside-down and backwards. In this case I kept it right-side up but then it looked like an elongated Flying Sub. Folding under the front and shifting it forward a bit took care of that and gave me a plastic sandwhich into which to add detail parts attached to the mostly flat surfaces.
The ship still lacked height so I added the two large short cones to the bottom, where they nicely nestled, flanking the cockpit root. Two BIC lighters also fit neatly between the two hulls. It still looked awkward in back, where the ship appeared to have little excuse to be wider than the engine. Two helicopter blades took care of that, looking like some sort of trailing control surfaces. Alas, it wasn't until later that I discovered that they would have looked better if I'd flipped them over, so that the line where they grew wider would follow the line of the trailing edge of the wings.
Rarely do I ever know how I want to paint a ship, but in this case knew all along that I wanted to paint it WWII Army Air Force brown over light gray.