That depends on whether you have a positive or negative slope.
a. If you had a positive slope and turned your line clockwise, the rise would decrease and the run would increase. If you turned it counterclockwise, the rise would increase and the run would decrease. For a negative slope, it is just the opposite.
b. With a positive slope, the slope would decrease if you turned it clockwise and increase if you turned it counterclockwise. Again, it is just the opposite with a negative slope.
c. The y-intercept would change based on how big or small the slope is, unless the y-intercept was directly in the middle of your line.