Once your axe head will slide stiffly onto the handle, the hardest part is done. Set the head aside for now and start shaping the handle, removing wood until the handle feels good in your hands. If you have big hands, leave the handle heavy. If your hands are small, make it more slender. Either way, make it graceful. If possible, keep a handle that you like close by to use as a reference. Take your time with this. I usually shape a handle until I think it’s done, then spend a day or two looking it over and handling it occasionally. Invariably I find things to adjust, spots to thin, angles to change. After a while, your handle will feel perfect in your hands.