I'm trying to slightly change the position of the map in my map frame but if I use mouse scroll for zooming, it's either too big or too small. How can I zoom/pan the amount that I just need?
In your Layout View, click the Navigate tool in the Navigate group and in the layout, hold the SHIFT key down and make a zoom-in box to zoom in just what you need.
When you Activate the mapframe in layout view look at the bottom left corner, there is a drop up! list that you can manually edit its value to the right scale. Pick something between those values that are too big or too small.