First of all add an Icosphere object with 1 subdivision, set the size to whatever you like (mine's 12).
Go into edit mode and use bevel (CTRL+B). Make sure to check "vertex only" and set the offset to a value of your choice.
Assign 2 different maerials to the pentagon (black) and hexagon (white) shapes.
Afterwards use another bevel command on the whole object. Set the offset to a very low value now, this is only needed to keep the penta/hex shapes when adding subdivisions later on.
Switch to Face select mode and invert the selection (CTRL+I). Use extrude individual with a high offset value, this should be ~4-8 times larger like you want the final result to look like.
Change the pivot point from median point to individual origins and scale up the penta/hex polys slightly to minimize the space in between. Afterwards extrude again but only scale down the faces, don't apply an offset.
Go to object mode and add a subdivision surface modifier with at least 2-3 subdivision.
For the final step add a Cast modifier. Keep the cast type (Sphere), and increase the factor to something like 0.75-0.85.
Higher extrude offset values from the step before allows to set the factor to a higher level and therefore turns the simple icosphere more into a perfect sphere shape.
For the low poly model redo the first step. Add an icosphere of the same size and use a bevel command with the same settings.
A simple tennis ball unwrap works quite well here and should give you 2 'rectangular' UV islands.
Switch to edit object mode and apply a subdivision surface modifier with just one simple (not catmull clark) subdivision. Afterwards add and apply a Cast modifier (sphere type).
Scale up the low poly model until it matches the high poly. Bake normal and texture maps.
