Long-serving winger Whalley has been in excellent form of late, having netted four goals in eight league games as Shrews top scorer this term.
And Town chief Cotterill, who claimed the League One manager of the month after an unbeaten December, believes 33-year-old Whalley can continue improving – if he can stop being upset when things do not go his way.
"I'm pleased for him and I really like him," Cotterill said of the in-form Whalley, who recently passed 200 games for the club and is out of contract in the summer.
"He's a lovely lad, very emotional, in terms of he wants to do so well – that when he doesn't do well it upsets him for a little bit in the game and he ends up losing a little bit of his rhythm.
"I said to him the other day that he's an experienced boy, an experienced footballer and experienced young man.
"Those slight disappointments of giving an odd ball away – it doesn't matter, as long as you work hard to get it back and give the next one.
"And I thought his link play at Wigan was the best since I've been here and it's no coincidence his link play ends up taking him higher to the goal later in a game and he ends up scoring."
After marking his 200th game for Town with a beauty at MK Dons in Sam Ricketts' final game in charge, Whalley netted a stunning late free-kick against Accrington in Cotterill's first league game.
He was also on target in the 1-0 win at Lincoln as well as a well-taken goal to seal a point at Wigan on Boxing Day.
Cotterill sees the task of improving all Town players as individuals, no matter the age, as something he is keen to do.
"Not only do I want to improve them as footballers, I want to improve them as young men," he added.
"You've got to improve the young man a little bit first of all, over a period of time hopefully I'll do that.
"But in any coaching and improvement, you can only do it with their consent. If they listen then hopefully they will learn because I'm a bit older than them."
Shrewsbury are still waiting to discover from the FA and its independent Professional Game Board whether their FA Cup third round tie at Premier League Southampton will be rescheduled, or whether they will forfeit the competition.
The tie was postponed from last Saturday due to a significant Covid outbreak at Salop.
Town and the Saints will both be in tonight's FA Cup fourth and fifth round draws, live on the BBC.
Meanwhile, League One high-flyers Portsmouth are reportedly interested in Town left wing-back Charlie Daniels.
Former Bournemouth star Daniels, 34, has made 16 appearances and scored twice since signing as a free agent in October but his short-term deal runs out at the end of this month. He has said he is open to extending his stay.