Above all, tell yourself a story -
* "I'm on my way to a business meeting"
* "I'm here to see my mate for a drink while he's in town"
* "I'm just on my way back to my room"
and COMMIT to that story, so that if anyone asks, it's what comes out of your mouth by reflex and it's what shapes the way you walk as you enter the premises - you have a reason and the right to be there, so why should anyone challenge you ?
Not that anyone will, except in maybe the snottiest hotel - tbh the staff on reception at TLs, PIs, HIEs and the like couldn't really care less if you there to fuck someone lol