The 27-year old striker, who has two goals in 10 internationals, is looking to establish himself in Gordon Strachan's setup this year.
Scotland take on Poland in a friendly in Warsaw on Wednesday night before turning their attentions to Euro2016 qualifiers and the Whites ace is determined to turn himself into an integral part of Strachan's squad.
"I don't think I've ever not been ready for international football because anyone who gets called into the Scotland squad is ready," he told the Daily Record.
"But in terms of being a regular around the squad, I feel as though I'm ready to really establish myself.
"Challenges in life are what drive you forward and getting Leeds back to the Premiership and Scotland to a major finals are two big ones. These are things I must try to achieve."
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