I remember my first knife and I still use it in my kitchen. The grind lines did not come up great so I ground the hollow grind bevel all the way to the spine on that one, and it came up looking pretty good.
Practice and more practice. Be patient and the work will start to look the way you want it too. My early grinding efforts involved grinding edge down for safety until I got comfortable grinding. Grinding edge down posed problems for me in determining where my grind line was and the angle of the grind.
Later I learned how to grind with the edge facing up and I got great results with both the quality of the hollow grind and grind line control too. It is easier to see the angle of the knife in relation to the belt grinder wheel. By grinding edge up the knife blank tends to dig in to the belt without using any real force, and this helps to control things more easill. I hope this is of some help.
Go easy and go slow. Contstantly look at how the grind is going and be carefull not to take off too much material too soon. Always, always keep the knife moving on the belt working aross from the tang to the point. Try not to stop this tang to tip movement or you will develop dips and other unwanted uneven grinds. Your grind should be a fluid like motion, keep the knife moving along the belt and be aware of where the belt is in contact with the steel.
As your grind line develops, keep it straight and gradually push it up towards the spine to where you want the grind line. Once the initial bevels look good then go from your 50 grit belt to a 120 and fine things up. By then it should look like a semi finished knife. From there go to a 320 grit and so on till you are done. I usually stop at the 220 grit, then drill out the holes for the handle, stamp my name into the blade and after that heat treat it.
Go easy, don't rush, and if it is frustrating you, get out of the shop for awhile go have a smoke and come back to it later.
