Raheem Sterling: England winger can be one of the greatest - Yaya Toure
England's Raheem Sterling can be "one of the greatest" but has to convert more of his chances, says his former Manchester City team-mate Yaya Toure.
Sterling has scored twice in 39 matches for England with his last goal coming against Estonia in October 2015.
Speaking to the BBC's World Cup Daily podcast, Toure said he sometimes laughed at the 23-year-old winger because of the chances he misses.
"He has to be more clinical," Toure said. "He can be one of the greatest."
Toure added: "He has pace, is clever and he can see. He's a technical player, like a Spanish player. Playing close to Sergio Aguero and David Silva he has learned a lot.
"Sometimes I laugh at him missing too many goals. He just has to relax. I know he works hard."
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The former Liverpool winger enjoyed an upturn in his goalscoring last season, scoring 23 for City in all competitions in comparison to an average of about nine goals a season over his previous five campaigns.
However, Toure believes there is still room for improvement and that Sterling is capable of breaching the 30-goal barrier.
"In the Premier League when you see how many times he changes the game it's impressive - and he's just scored over 20 goals. For me, he should score maybe 30.
"I remember in one game he missed two or three. At half-time in the dressing room he had his head down and I said: 'Don't worry, you will score.'
"When you have Kevin de Bruyne, David Silva and Leroy Sane, the balls are going to come 100%. When he came in after the second half he had scored two goals and it was brilliant. He came over and said: 'Uncle, thank you.' He calls me Uncle Yaya, he says that all the time."
Toure on England defender Kyle Walker: "He is one of the best right-backs, with his pace and his power. He is just incredible. I remember when he was at Tottenham, I hated to go on his side because he was so quick and powerful.
"He's best in this position, his defending and attacking are good, he's full of energy - always up and down and he must be one of the quickest right-backs in the world.
"For me, playing Walker in the three at the back means England lose something. With his power and pace, it would be better to put him at full-back because he's going to create more danger sooner."
Toure on England centre-back and former Manchester City team-mate John Stones: "In the past I was used to playing with defenders who were older than me but John was younger. At the time I was playing with Lilian Thuram, Rafael Marquez and Carles Puyol and they were aggressive and more secure. The new generation of defenders can take the ball through the middle.
"A strong part of his game is heading. He's very good at set-pieces and he's very good with the ball. What I'm scared about with him sometimes is his level of mentality because when he made a mistake that cost him you can see it on his face.
"In football, you have to have a strong mentality and John needs that a lot. If he gets it he can be one of the greatest."
Toure on the influence of 'big' foreign managers on the England team: "With powerful clubs, like Liverpool and Manchester United, who have big financial power they can buy big managers and that's a benefit to the young British players.
"When you see how a country like Spain won the Euros [2008 & 2012] and the World Cup , they won because Jose Mourinho had been passed to Real Madrid and those big managers were passed to Barcelona and that's what those players can then bring from their club to their countries."