as soon as you’re glad with the basic shape, give it a Subdivision Surface, give it a value of 2, it will round everything, so you need to add some edge loops to give some corrections, and work again. For Unity I think you’ll need to apply the modifier (put your mouse over the modifier and press Ctrl A) BUT always keep a version with the modifier non-applied (i.e. “low-poly”) so that you can always make easy changes. It’s always more tedious to work on a high-poly mesh, plus it may slow down the computer.