Why I'm going to be picky with markets
Not every market is going to be for you, and that's okay!

I've done a lot of markets this year. For me at least. And part of that is because online sales have been slow, so if I've found a market that I think might be worth a try then I have applied.
However, footfall and spending has definitely been lower this year.
But that's not all that is affecting sales.
Not all markets are for me. And that's fine! You don't know until you try if something is going to work for you, and the big thing I've realised recently is that small, local markets are not for me.
Why?
There are several factors:
The customers/target audience:
I find that local markets have a lower footfall in general, and I happen to live in an area of the country where (it feels to me at least) a lot of older people seem to live. And whilst I do get older people buying my products, they are not my prime target market (which I'm pretty sure is mostly 20-40 and female). I've had a lot more success at markets where the customer base is a lot more varied, and where younger audiences are - 20, 30 year olds as opposed to 60, 70 which feels more common at local events.
Free entry vs paid entry
From the markets I've done, the free entry markets are usually where I make less sales. Footfall in some cases has been great, with some being in great locations, but the amount of sales in comparison is very low.
I think when something is free, people are mostly there to have a nose, somewhere to mooch around and have a look, which is fine, but it means that you are less likely to make a sale, as they probably wouldn't have come out with the intention to buy anything, and just stumbled across a market.
Paid markets on the other hand, have been way more successful for me, and where I have had my best market sale days! When people have paid to be there, there's more of an expectation of 'oh I'm probably going to buy something' to make the entry fee worth it. And people intentionally go to most paid events, and less likely to be just passing traffic (although some will be!). Paid events are often niched events too, which helps with being able to reach a target audience. Back when I did Disney inspired, I did a market called the Magical Market and pretty much all vendors were magical inspired. It was my best market I've ever done (£2k 😳), a market that I don't think I'll ever be able to beat, but it was great because it was for a niched audience, who also paid entry.
I have a event coming up at Cats Protection, where I currently volunteer, and I'll be taking all my cat products, so I'm really curious to see how that one goes as that definitely will have my target audience there!

Other sellers
Local markets tend to be smaller, usually around 20 or so stalls, and the few I've done multiple times, I've noticed there's also been a lot of the same people there every time. It gives a feeling of community, but also in my personal opinion, it can be a bit clique-y. At my most recent market, I was also probably the youngest by about 20 years - and I'm 33 - so the vibes of a lot of what people were selling was very much more craft and hobby type products, and I just didn't feel I fit the vibe. I didn't feel hand made enough? Even though of course everything is designed and a lot is printed by me 😅
Events that are curated usually do much better, because there's a variety of different products and not anyone too similar, or maybe there's a theme to the market. Some of the markets I do regularly make sure to change up the vendors so that there isn't the same people there every time, especially if it's a competitive product category - illustration/stationery (so, me), candles, crochet and jewellery seem to be the most hotly contested product categories!
In conclusion?
I most likely won't be doing smaller local markets from now. Local markets are definitely cheaper to vend at in terms of stall fees, but you still need to account for things like travel/parking, food and just your time being there. Standing around for 6-7 hours to make £50 is not really worth your time, even if the table was only £20.
Doing events that you can see will cater to your target audience, are well advertised and marketed, and are curated will more than likely bring better results. Obviously it's not guaranteed, as there are way more factors that can alter the outcome of events as well - the weather is a big one - but you're likely to have a better time for sales, which, at the end of the day is what you're there for!