Your technique is wrong for any type of stone or diamond sharpener. Do not rotate your blade in a circle! You are ruining the edge you just put on. ..... This is hard to explain, but very easy to demonstrate. For the very best cutting edge one needs 3 grades of whet stone; coarse, medium and fine. The angle of the cutting edge needs to be between 11 deg. and 15 deg., depending on what you have to cut and what you are sharpening. Start with the coarse stone and shape the blade uniformly from hilt to tip by placing it on the stone at the correct angle, edge facing the movement and drawing the blade towards you one to three times. Short blades can be totally covered in one pass, long blades might need to be done in halves, ie. back half-front half. Reverse to the other side and push it away from you one to three times maintaining the correct angle. When the blade is shaped go to the medium stone and do it all over again. When you are satisified that you can not improve the cutting edge with the medium stone go to the fine stone only go down to one to two strokes max per side and then reverse.
I like artificially made stones for coarse and medium always used with lots of cutting oil and then a natural "hard Arkansaw black" fine stone. The cutting oil should be medium weight for the artificial stones and then very light weight for the natural fine stone. The technique is hard at first, then you develop muscle memory and it becomes easier. After a blade is shaped once, one very seldom needs to use anything except the fine stone to resharpen. Brownells Gunsmithing Supply catalog is a good source for the Arkansaw Black fine stone and the proper cutting oil. You can find the artifical stones at any hardware or Sears. Old black/fine whet stones can be found in used tool stores for next to nothing because they are "cupped" from use. Buy them! Any rock hound with a polishing table can true them up for you with minimum effort.
For a razor sharp cutting edge, after the above is finished find a hard piece of plain leather. Place it on a hard surface and "strop" the blade a few times on each side. Stropping is backwards from sharpening. Place the edge away from the draw and pull/push the knife blade backwards with light pressure on each side. If everything has been done properly, one can shave the hairs from one's arm. This is assuming that the steel in the knife blade is of good quality. Usually only expensive knives have decent steel in the blade.
Your diamond stone should be use dry and only as a "coarse" grade stone. All cutting edges should be customized for what you are primarily cutting. A hunting knife for gutting and skinning a deer can be sharpened to a medium sharpness with a saw tooth effect whereas your caping knife needs to be much smaller and just as razor sharp as you can get it. A "Swiss Army" knife large blade for general use can stop at the fine stone and omit the leather stropping. Strop the little blade on your Swiss Army. It is nice to be carrying at least one blade that is razor sharp. Your steak knives can get by at the "medium" stone level. If you are an electrician, you can just go find a concrete step and sharpen your knife there on the concrete.
No machine sharpener will approach the edge that one can get by using the above technique. The effort is worth it to learn. You will also find that you are no longer interested in "cheap" knives that will not hold that great edge that you so laboriously created.