Scott Parker is confident that Fulham will learn the lessons of their Premier League failure in 2018-19 after securing a return to the top flight.
Fulham won promotion from the second tier via the play-offs two years ago but, after an expensive recruitment drive, went down after only one season.
Parker led Fulham back to the Premier League with a 2-1 win over Brentford in Tuesday's play-off final at Wembley.
"There were some clear errors made last time," said the ex-England midfielder.
"We will learn from that. We need to learn from that.
"We're going into the best league in the world, the best players, the best teams… it's a brutal league and I realise the challenge ahead.
"What we're trying to build and what we're trying to engrain in these players, in this football club, is some core foundations.
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"Sometimes those core foundations get you far in life. You can have as much talent as you want but, if you're not building your football club on concrete and you're building it on sand, then in the end it will be the rollercoaster ride.
"I hope we can grow gradually. It's going to be tough but, if we can't, we have core foundations that we always fall back on."
Fulham spent more than £100m on new players after beating Aston Villa in the 2018 play-off final, but they struggled throughout the following season and were relegated with five games left to play.
Slavisa Jokanovic, Premier League-winner Claudio Ranieri and Parker - as caretaker - all had spells in charge but could not save Fulham from the drop.
'Give it a go and let's see what happens'
In his first full season at the helm at Craven Cottage, Parker led Fulham to fourth place in the Championship and eventually promotion, with left-back Joe Bryan scoring twice in extra-time in the final against their west London neighbours.
Bryan's first goal was a 40-yard free-kick which caught out Brentford goalkeeper David Raya at his near post.
Parker, 39, said: "We did our due diligence on the keeper and the keeper's got a very aggressive, high starting position from wide free-kicks.
"We brought it up in a set-play meeting and spoke to Joe and Harrison Reed, who would have been on the opposite side.
"I just felt when we brought Aleksandar Mitrovic on, Joe was going to cross the ball, because obviously one of Mitro's big attributes is heading, so I called him over.
"I didn't want to let on to Brentford's bench, so I tried to bluff it a little bit. I just said to Joe: 'Listen, I want you to go for it. I want you to commit to it. I want you to really give it a go and let's see what happens'.
"Thankfully, it's gone in. He's got an unbelievable left foot."
'The sun will rise again tomorrow'
Brentford, who have not played in the top flight since 1947, have now had nine unsuccessful play-off campaigns in their history without winning promotion.
They narrowly missed out on two fronts this season; victory in either of their final two league matches would have been enough to send them up automatically ahead of West Bromwich Albion, but the Bees rounded off their campaign with losses to Stoke and Barnsley.
After his side's extra-time defeat at Wembley, head coach Thomas Frank said: "The sun will rise again tomorrow. It is not the end of the world. Of course I'll be very sad tonight and disappointed, but that's the way it is.
"I just know, in football and life, you need to be strong because there will be situations that do not go the way you wanted. You need to show resilience.
"If you want to achieve something big you need to be able to bounce back from setbacks, and I know we are coming back even stronger next season, I'm 100% sure of that."
Failure to reach the Premier League is sure to bring questions about the futures of some of Brentford's star players, such as top scorer Ollie Watkins and winger Said Benrahma, who have excelled at Championship level this season.
Asked if he is confident of keeping his squad together next season, when Brentford will move into a new stadium, Frank replied: "It's not my biggest concern right now.
"The reason why I'm most down at this moment in time is mainly for the fans, for all the people who have been at the club for many, many years, they deserve so much to be in the Premier League.
"And I also care about, and believe so much, in this group of players, and I'm very disappointed that we're not going to have the opportunity to attack the Premier League.
"Nobody knows what it going to happen tomorrow. I just know one thing: we'll have a very, very strong side going in to the Championship next season."