The stand-up, compère, act booker and manager Geoff Whiting told me that many years ago he was an open-spot on a bill with Ross Noble, who is renowned for his improvisation and for doing material that is bespoke to rooms and towns he is playing in:
“Really good comics can get material out of the room. It seems like it’s off the top of their head, but they’ve really been sat at the back asking, 'what’s funny about the room?' Ross was one of the prime exponents of this. He started aged fifteen—I can only think of one comic who started younger than that—and I saw Ross when he was seventeen and opening a show. He was already doing twenty minutes at that age.
From where Ross and I were sitting at the back waiting to go on, we could see a fire door where they’d painted flames round it. He managed to get two or three minutes expanding on why it was an absurd idea. Stuff like: when it’s not on fire it looks like it is and if it is on fire you wouldn’t notice. He deconstructed the whole thing and he was hilarious, people were rolling about. And yet I’d been sitting looking at it too and I hadn’t really noticed it. I’d just been thinking about my set. But of course, you learn and now if I spot something in the room, I will comment on it; not that you can ever become a Ross Noble.”
If something suggests itself, a comment about the room or the context of the gig can be a quick way to get a first laugh. An example that comes to mind is a quip Ricky Grover came out with at the start of his set on the now defunct BBC TV programme The Stand-up Show. This was before the days of the rock-and-roll style Live at the Apollo and the set was an intimate largely wooden affair. He remarked:
“It’s great here, innit? They must have spent about thirty quid on wood alone.”
This then led into a strong gag Grover would often do at the start of gigs (he is a big guy):
“I nearly didn’t make it tonight. (POINTING TO EDGE OF STAGE) There’s a step there and everything.”
Here he gets two good laughs well within the first thirty seconds. It's great if you can start off with a gag or two that is (or seems to be) specific to that show on that night. In the above example, one genuinely is bespoke for that room and one he regularly used at the start of gigs. Even the apparently bespoke one could have been a line he used in different settings. It would easily adapt to other contexts. You can imagine him saying elsewhere for example: “‘They must have spent thirty quid on mirrors alone.”’
You can also have a line in the set that is adapted according to where you happen to be saying it. For example, I'm working with a comic at present who has some material on Croydon; which is where he lives. I suggested that he always start this material by comparing the place he is in to Croydon. When we last spoke he'd done a gig in Hampstead. He was surprised by the size of the laugh he got when he playfully compared the two places. The comic idea wasn't hilarious but people tend to laugh more at an idea when it is bespoke to that gig or feels just for them. That's why cock-ups or ad-libs can get such great reactions - people love it when they feel they're seeing something that doesn't normally happen.
This is writing on the evening of the performance with the specific venue in mind; recall that writing need only be notes or even be entirely in your head. The gags and material that are genuinely bespoke to that night, or at least seem to be, tend to be easier to get laughs from as the audience laughs more readily at remarks that appear to be spontaneous. I know comics too who Google the local newspaper on the way to the gig to see if there’s something that’s been happening that they can refer to. “I see your MP is in trouble again…”
Also, if there's a problem, or something weird about the night, or there is something striking about you—such as you’re a look-a-like or exceedingly tall/ fat/ thin etc.—then address it head on. It'll remove the distraction and, if you have any difficulty that might make the audience uncomfortable, making light of it and showing you’re relaxed about it means they will be too. Furthermore, getting in early with a gag that's about your own appearance, failings or inadequacies can be a quick way to get the audience to warm to you and also cuts out heckling possibilities—you've already laughed at yourself.
Homework:
When you arrive at a gig, what do you do? Talk to the other comics or the venue staff? Chat to members of the audience? Hide? Lie down with your eyes shuts and headphones on? Pace up and down outside? Of course, you must do what you must do before a show, but being alive to the environment and context of the gig can pay great dividends. Engage with where you are, lift your head up and observe. Think, write.