Silver is very hard to get the wet look,the last one i did was a new bmw and even with a swissvax wax its didnt look amazing like a red or black.

Do the usual decontamination clay/iron x ect.
Then get the clear nice and level (ie swirl removal) spend some time burnishing with a nice fine finishing polish,then maybe use a sealant like werkstat.

Bugs should come off easy enough when washing if you have protection,and for tar you need some autosmart tardis.