Rooney, whose success with United includes winning the Premier League twice and triumphing in last season's Champions League, added: "After we won the Champions League we were thinking about the start of the next season straight away.
"The manager said 'make sure we're ready for next season'. It is something that you have to do. You can enjoy the night when you win trophies but after that you're looking forward to winning them again."
And Rooney believes England have cause for optimism under manager Fabio Capello as they chase a first major trophy since winning the 1966 World Cup.
"Since the manager came in the routine has changed and the team started playing a lot better football," stated the former Everton forward.
"The main aim was to get wins in qualifying games and we did that, and thankfully I was able to score some goals.
"Of course it is every player's aim to win a trophy with England. It is something that hasn't happened in many decades now.
"If we could do that in the next few years I'm sure everyone - from the fans, the players and the staff involved - would be absolutely delighted."
England are well placed to qualify for the 2010 World Cup in South Africa, having won their first four games to top Group Six.
Victory over Ukraine - the only team Capello's men have yet to encounter - would give England one foot in the finals with only half the campaign completed.
"We had some great results and performances in our qualifying games last year," continued Rooney.
"Now we have some important matches coming up and we must not get complacent."
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