Ive got a new cam for the cheeky, and was wondering how to fit it!
Ive got the haynes so thats a start, but unsure whether to replace the bearing shells that it runs on.  Its not a brand new cam, its from a Punto 75.

You dont normally have to replace the shells - 9/10 they arent removable and are an expensive machine refit.

Inspect them for any wear/scratching would be the sensible thing to do.

Test fit the new camshaft and if its higher lift make sure it will clear the head at each side during a full revolution, as you would usually need to get the head modified for camshafts with a much higher lift than normal.

Time the cam EXACTLY to the spec shown in the cam card - DO NOT approximate - they come with specific timing requirements for a reason. Youll need a dial guage to find true TDC and a degree wheel for indication.
I would also invest in a vernier pulley.

EDIT - Ignore the run in bit that follows, as its not a new camshaft:
When you have the camshaft in, check the valve clearances. You may need to reshim.  Reshim accurately or you end up losing power or at worst case, wrecking your engine.

When you have finally torqued the camshaft in and all is well, grease it up real good. this is important. Once you start the car DO NOT ALLOW THE CAR TO IDLE FOR THE FIRST 20 MINUTES. KEEP REVS ABOVE 2000 OR SO AND ALTERNATE ENGINE SPEEDS. This is the one and only chance you will ever get to ensure it wears in correctly.


Other things you could do when youre at it (Require head off usually)

install higher rated valve springs
change valve stem oil seals
clean valves - this is a good idea regardless
clean combustion chamber - as above

soopahfly if only your new avatar was a bit better quality and looped well that is cool

Best I could find