In no particular order:-
1) What's the weather like, and is it likely to be different in different areas/directions? What's the cloudbase, and will I have to cross any mountains?
2) Have I been there before; I like trying new places, and getting new airfields in my log book.
3) If I've been there before, is the food good? Do I have friends close by who might like to meet me for lunch?
4) Do I have a free landing fee voucher from Flyer or Pilot?
5) Is there anything interesting to see when I get there, especially if it's on the airfield, such as a museum?
6) How long do I have the aircraft for, and how rich am I feeling, ie how far away can I go?
7) Do I want a challenge, or just a local jaunt to somewhere I know and love?
8) Where are others going; maybe we can meet there, ie a "fly-out".
9) Do I want an interesting/new challenge on the way, eg grass runway, controlled airspace, challenging nav...whatever might stretch me a bit, if I feel like being stretched.
10) Where do I...er..just fancy going? I'll just look at the map and see what grabs me.