DO NOT choose 23 words that appear in a row.
DO randomly come back to your screen every few minutes and look at the word on the screen. Do this 23 times.
Find the 24th word by trial-and-error: only one out of every 256 of the BIP-39 words will work. Try BIP-39 words 1-256, or 257-512, or...or 1793-2048 until you get a valid seed phrase. You will want to use a wallet that quickly shows you whether your 24th word is valid, without having to re-enter your first 23 words.
You can find the BIP-39 words here: https://bip39-phrase.com