Hey Sokota,
I think your run is close to looking good. Here is what I would do (though I know little so take it with a grain of salt...):
1. Your run (without idle), is 6 frames. The chart that Draco posted uses 8, which seems like a good amount. The two frames you are missing are the "recoil" ones, which are pretty important as they make it look like the character is impacting the ground. In your animation now, that frame is skipped and the leg is drawn back without even touching the ground. This makes it look like he is kind of gliding. So, add in those recoil (or "landing") frames and I suspect it will look a lot better.
2. Don't recycle the same frames over and over. Right now your frame 6 is just a copy of frame 3, and that makes it look weird. It looks like the nearer leg is is extending twice, and the far leg never gets extended out. We can tell the legs apart because of the highlight in the nearer one, and the line along the back of his shorts.
3. The arms should move like a pendulum in opposite directions of the legs. Once you make a new frame for the back leg extending out, then the arms should be in the opposite position as them. Right now, because you are recycling frames, his right arm only goes to his side and back, and his left only to his side and front.
4. Don't straighten the arms. In your frame 1, the arm is nearly straight, and it pointing forward with the leg. Keep the going in mostly opposite directions so the character looks balanced.
Also, don't use the idle frame in the walk, because think about it. Are both your feet ever together on the ground while you're running? No. The only time the legs are together is when one is "passing" the other, and it is bent at that time.
Hope this helped, good luck.