Mel was appointed as Steve Clarke's replacement earlier this month and will take charge of his first West Brom game when Roberto Martinez's side visit The Hawthorns.
The Midlanders have won just once in their last 11 Premier League matches, while Everton have lost just twice all season.
However, Mel claims the work done in training since his appointment will translate into the match.
"It's still very soon, but it is something that will be noticeable," the Spaniard told West Brom's official website.
"Previously (under Clarke) very good work has been done. It's not a case of doing a better job or worse job, it's doing a different job."
Mel also paid tribute to his opposite number at Everton, Martinez, saying his compatriot should be very proud of his work in England.
"We're friends, and his technical team are also friends," he added.
"Roberto started at the bottom here in England, and it's admirable he is now with a big team."
