DressingThe purpose of dressing is to restore the correct cutting action of the wheel. Dressing removes the clogs on the surface of the wheel and the blunt grains of the abrasive, exposing the new sharp abrasive grains of the wheel which can be cut and brought to shape efficiently. 
TruingTruing refers to the shaping of the wheel to make it run concentric with the axis. When a new grinding wheel is mounted, it must be trued before use. The cutting surface of a new wheel may run out slightly due to the clearance between the bore and the machine spindle. Grinding wheels, which are in use, also can run out of true, due to uneven loading while grinding. 
Dressing and truing are done at the same time using same tool.

Soluble Oils are metalworking fluid concentrates containing a high percentage of oil (usually greater than 50%). When mixed with water, they form an emulsion that has a milky appearance. The high oil content provides excellent physical lubricity for the cutting operation as well as protection for the machine tool.

Grinding with a balanced grinding wheel will make it possible to achieve the required dimensional accuracy with surface finish.