Trumpism is a memeplex
A meme is an element of a culture or system of behaviour passed from one individual to another. It can be literally anything from an idea to a behaviour to how to use chopsticks to a dance to use of the word noice.
A memeplex is a cluster of memes which are mutually reinforcing
Trumpism is such a cluster. With a strong meme at the centre (Trump himself) and many other memes which reinforce Trump to their own benefit.
Trumpism was originally smaller, however other memes (ie public figures) decided (often correctly) that their own memes could grow if they aligned with Trump. So they support Trump, tapping into that energy while adding to the energy around Trump himself
To replicate such a dynamic, one needs a central meme (or, leader) who is popular and memetic enough that influential others feel that it's in their self interest to support your leading meme.
I expect this would need to be done over a long timeline, in order to build the brand. With the dynamics of modern media, that timeline could be shorter than it used to be, however I think Trump and Farage have both benefitted from being public figures for over a decade now. In other words, their memes took a while to reach sufficient strength that many others would start trying to align themselves with them, and thus enter their memeplex
As well as a strongly memetic leader, one also needs enough influencers who will be receptive to their message. I think this might partially compensate for weakness of memetic strength of the leader, but a better way of thinking of this is as a 2nd angle of attack: go for memeticity of leadership then make the memes easy to support for the people you want to support them. If such an ecosystem of candidates already exists, then great! If it doesn't and you're playing the long game, you may want to invest in 'seeding' potential influencers: lots of low-cost, low-chance-of-success, high-reward bets. Such a seeding process might look similar to a startup incubator, but for ideologically aligned and promising influencers.
"Influencers" here means anyone with any form of public following, not just people who's main income comes from social media accounts.