Although it is possible to choose quite dissimilar objects to morph, objects that are closer in their original form are easiest to work with. In other words, a donut can be morphed with a cathedral, but it is far easier to make the morphing work with the donut and a car tire.
When adding shadowing and effects via Layer Styles, it is best to save them for last because adjustments that you want to make (but do not use the global angle) may be difficult to weed out and correct. If you use the Global Light for all Styles, the effects can be collectively adjusted using the Global Light dialog box (Layer, Layer Styles, Global Angle). They can also be changed in the Styles dialog box, which appears when you select any effect from the layer Styles submenu. You can use Styles with different lighting angles by unchecking the Use Global Light check box for that particular style.