Raise the wheel off the ground and spin it forward. With your fingertips gently touching the bike frame, do you feel any vibration resonating through the frame? Do you hear a grinding noise?
If so, it is being caused by your bearings riding on a worn axle cone. No check the wheel for looseness. Raise the wheel off the ground and as you hold the bike with one hand and grasp the rim with the other, try to move the rim side to side. Do you feel any looseness? Yes? The cones are loosely set and need to be tightened. No? Then they may be fine.
If you have determined that the noise has been caused by worn components, then it is time to overhaul the hub, or take the wheel to a mechanic. Replacing the internal parts may mean changing the axle set, cones and the bearings. Plan on spending a minimum of $10 for parts and perhaps a lot more; depending on the quality of the wheel.
For further information you can seek out instructions through on-line videos, books or private instruction.
Next, a basic look at wheel alignment.