Spending time in the NFL and studying Germany and Spain's World Cup wins has helped England improve their set-pieces, says manager Gareth Southgate.
England have scored more goals from free-kicks or corners than anyone else during the World Cup group stages.
"When we analysed Spain and Germany in particular, they were probably better at set-plays than the perception might have been," Southgate said.
"They were a bigger factor in them winning than maybe people realised."
England play Belgium on Thursday in their final Group G match, with both sides having already qualified for the last 16.
The Three Lions have had 16 attempts at goal from set-pieces in their opening two matches, more than anyone else.
Speaking to BBC Radio 5 live's World Cup Daily Podcast, Southgate said: "Set-plays are a high percentage of goals scored and goals conceded. In tournaments that seems to become even more important."
"Both Spain and Germany play fabulous football but when you looked at how many set-play goals they'd scored - or in Spain's case, how few they'd conceded - that was definitely a key part of them being successful."
Southgate visited NFL side Seattle Seahawks and attended two Super Bowls prior to the World Cup.
"You're always learning and we had the chance to interact with lots of different coaches," Southgate said.
"Some that travelled out went into think tanks on various different issues on managing people and leadership and detail within games.
"You're always trying to bring new ideas to your team and new ways of thinking, and anything that can possibly add to what you're delivering."
Allan Russell, a former striker who played in the Scottish lower leagues, has been credited for improving England's set-piece play.
Striker Harry Kane said Russell had been working with the side on their attacking set-plays, describing his work as "little stuff to maybe give us an edge".
"Allan has an attention to detail that I liked and thought it was something we hadn't necessarily put some additional focus on in the past," Southgate added.
"He's become an important part of our coaching team and our whole support staff."
"We won't have success in this tournament without every department in our staff doing their job to the highest possible level."
Goalkeeper Jordan Pickford, speaking on Tuesday, described set-pieces as "crucial in tournament football".
"We've scored six out of eight set-pieces but we will carry on working on it," the 24-year-old said.
"We do all our training and at the end of the session we have 10 minutes of set-plays with the attackers at one end and defenders at the other."
Tottenham full-back Danny Rose says Southgate can be "too nice at times" but the players "know not to cross the line" with him.
Rose says England assistant manager Steve Holland is the one who "gives you a grilling".
"I think the coaches have a great set-up," Rose told Radio 5 live.
"The gaffer is really relaxed and approachable and Holland is the one, who if you step out of line, do a bad pass or are late, gives you a grilling."
"They have got the balance down to a tee."
"Everyone is on Steve's back in training because he is normally the referee, the gaffer just sits in the background and has no part of it."
Source: BBC