I’ve seen this topic come up a few times so I thought I would share the method which I use.
First you want to go here and generate 1000 words (feel free to do more or less depending on your comfort level) (Random Word Generator — Get a list of random words)
Next copy and paste them into here: (https://accelareader.com/)
What this will do is go through all of the words at whatever speed that you set and your goal should be to make an image for the word as quickly as possible.
If your doing this for the first time you might struggle to keep up with 40 wpm but if you do at least a thousand words every day you will start to see repeat words very frequently and you will be able to recall the image you made for that word faster and faster until you eventually reach a point where you can unconsciously recall the images you previously made for that word with no effort.
The key idea here is to continuously flood yourself with as many words as possible which will force you to quickly come up with images and over time you will build up more and more images and get faster and faster at recalling repeated words.
After around a month (30,000 words/images) you should start to feel very comfortable with translating words and abstract concepts to images.