Phone up the management beforehand, claim to be a personal assistant of a VIP [you, make up a nice story] from [insert random country of your choice] and ask to get a spot on the guestlist for a particular date. Might work if it’s some real exclusive upscale club. Heard that this worked at least once.
From my own experience working in that field:
People who always have guestlist spots: DJs & friends, club photographers, friends of the promoter. If you’re good at bluffing you might try to pass off as one of those people. Claiming you’re on the list and saying a random common name like “Alex” might work too if you’re lucky. I used to DJ and therefore got guest list spots for friends when playing out, several times when I arrived with said friends in tow somebody already got in under their name. Guess somebody did just that.
I’d recommend you do your homework though, either know the name of the promoter or one of the DJs and claim they put you on the list, you might get in if you’re lucky or friendly and persistent.
A clever tactic I heard of was people saying a random name, and trying to catch a name on the real list while the bouncers scan the list openly for the random name. If they say “No, sorry”, go “Oh, maybe he put me on as [name you got from the real list, say it’s your nickname or something]...” – result.
Also one thing that worked for me once when I was on holiday in Ibiza was claiming to have already been in the club and not having gotten a stamp on my arm. (stupidest excuse ever). Oh no I’m a stupid wasted clubber etc. Got asked how much entry I paid (knew the price from flyer), got let in “again”.
If it’s just a question of wanting to get in (paying customer), dress up stylishly, exude some good party vibes and go with some good looking girls and go early. This way you’ll have way more chances than coming late, without girls, dressed mediocre.