The Baggies have already guaranteed themselves a fourth successive campaign in the Premier League.
But Clarke knows eighth-placed Albion have to continue to look to strengthen in the summer.
"We have been thinking about next season's plans since September last year," said Clarke. "It's something we're always looking and thinking about, how we can improve what we have.
"We would like to think that's going to continue, but if you stand still in the Premier League, other teams come charging past you.
"It's important we don't stand still, it's important we look to improve the squad we have and give the players we've got a bit of help for next season.
"That's something we will endeavour to do between now and the kick-off of next season.
"Whether they are resolved early in the summer transfer window or whether we have to wait until July-August time, only time will tell."
This weekend, West Brom face Arsenal, who remain in a battle for a top-four finish after what has been an inconsistent season.
Gunners boss Arsene Wenger has come in for criticism this campaign but Clarke feels he deserves time to continue the philosophies he has preached during his 17 years at the club.
"Mr Wenger had a great start with Arsenal, winning trophy after trophy, so you buy yourself time to be able to develop young players and bring them through," added Clarke. "Most people at Arsenal would say he has done a great job there.
"If he has a season that's a bit more disappointing than others, surely they are going to stick by him, see it through, give him the chance to keep building the squad and try to challenge for honours.
"You've got a lot of big teams who spend a lot of money and want to finish in the top four - but not everyone can."