I’ve come to love, adore, live by the Electric Bastionland tables. A combination of evocative, weird and compatible makes them just work so damn well for what I tend to run.
Thing is, I want to make my own. I want to learn how to perform this cognitive connective magic.
How do I do it?
My main advice is that you’re looking for evocative and precise words.
The EB spark tables are two d20 lists of words right? So how you do it is you just … do it. Write out two lists of 20 words and then start rolling. If you get some results that don’t fire your imagination, one of the words in them isn’t pulling enough weight and needs to be changed.
Generally you want to avoid stuff that doesn’t link to an immediate image, concept, or action. So for example ‘nice’ is a word you’d want to avoid in a spark table, as it doesn’t evoke much. ‘Immaculate’ has a positive meaning but is more interesting (in my opinion) because it’s more specifically evoking a unique quality. So a ‘nice garden’ is boring, it’s something you’d say in small talk. An ‘immaculate garden’ is more interesting to me because it suggests someone is keeping it that way. It’s more visual and creates a question as to who keeps it immaculate.
I actually think writing poetry and writing random dice tables have a lot in common, you need to be really economical with words and each one is bearing a lot of weight meaning-wise.
I talk about how to make Spark Tables here.
I’d write down words that evokes the kind of physical landscape and mood that one is trying to evoke.
A lot of the results in the EB tables have a double meaning, literal or metaphorical like ‘dirty’, I’d try to have at least some words that work like that.
I’ve been making a lot of Spark tables, and similar, recently. A couple things that I’ve found helpful:
Go through the places, people and things in your setting and write down the words that you are using to describe them. Sometimes I think about a spark table as created by taking apart the world of my game into its constituent, single-word parts and keeping the most evocative and representative bits
Keep testing words as you add them. Rather than rolling on the table, I usually just do this mentally. Add a word to one table and then run down the other table combining it with all the words there. In a couple seconds, you can usually tell if it’s working
Spark tables often have an implied or explicit order. Roll on table 1 first, then combine with table 2. If after testing a word (see point 2 above), it doesn’t work in one table, trying putting it in the other table. Table 1 words usually read as descriptors, and table 2 words usually read as the object of those descriptors.
(Of course, this doesn’t mean that Spark tables have to have an order! But I’ve noticed they seem to develop one, whether intended or not)
Maybe watch a movie or show that you love (and feels adjacent, at least in tone to the kind of story you want to generate), and write notes while watching, cooking dinner, etc. Hit “pause” if you need time to write or think about a tangent.
I like listening to music and browsing through Pinterest for inspiration. Listening to this song by Kenji Kawai inspired my idea to have a campaign about gods and oracles – surprisingly, closing my eyes made me think of Greek or Norse gods, instead of cyberpunk or anything Eastern.
I watched Princess Mononoke last night. First time in a while! (On HBO Max currently.) Feels exactly like a cool OSR adventure, to me. 
The advice about double meanings is definitely worth noting. The EB spark tables only give you two words, but they’re often words that have multiple interpretations or could lead your mind to several different images. This kind of language use is difficult to teach quickly, but my advice is to spend some time with a thesaurus because you build up a mental map of how different words relate to each other, what their individual tone is, etc.