There is technically no one best way to sell. Buyers have different taste and wallet.
But desirable and more likely to sell at a faster rate in order but never guaranteed:
single dictionary word
two word (if top rate— average has too much competition)
single popular dictionary prefix/suffix
made up words empty vessel 4 letter and up (takes longer to sell but many prominent companies go this route) has to be a great one short catchy easy to read and say.