This is how I develop games...
1. I first make the basic graphics. Like the main character and the tiles for the first level.
2. Next, I make the basic engine. I will use this to test out my character's movements and make sure that everything looks good in the game.
3. After that, I make more graphics. I add animations to my main character, add more tile animations, and make at least one enemy.
4. Then I make a better engine and the first level. I will add better gameplay (like health and enemy AI) and I will start the level design process. At this point, I usually make a main menu as well.
5. Then it's time for final details. I finish the rest of the levels, make bosses, make music, and do all of the debuging.
6. Finally, I compile my game
It's pretty basic but it works