"You never know what will happen next. You can do all the planning under the sun, then something small tips the balance, and all your plans go out of the window. But that element keeps you on your toes, and ensures that you remain flexible in your approach."
At the outset, Mrs Muir felt that she did not possess the necessary personal resources to tackle such a demanding role. Yet 11 years down the line at Litchard junior school, Bridgend, and she is the holder of the Welsh special needs teaching award for 2006.
"My advice to anyone starting off in special needs is to keep at it. There will be times when you feel like giving up, and there'll be times when you'll go home feeling drained, but the kids are smashing to work with and the rewards are huge," she says.
Parent Joanna Matthews nominated Tracy Muir for the Plato as a thank you for nurturing her 11-year-old son, Gareth.
"Since being in her class, Gareth has made huge strides. Mrs Muir recognises the potential in all her pupils and brings out the best in them.
She's always there for us parents too, and she provides us with a great deal of support," she says.
At Litchard junior school the special needs pupils from Year 3 to Year 6 are all in the same class, a total of 14 children. They have a range of problems from physical difficulties such as sight and hearing impairment to emotional and behavioural difficulties.
A collaborative approach is taken in the preparation of individual action plans, and parents and pupils are invited to contribute in identifying the targets that are to be met.
Setting challenging yet achievable goals plays an important part in raising a child's self-esteem which, according to Mrs Muir, has already been dented before a child reaches school age.
"Children realise quickly that they are different from their peers, and that soon has a negative impact," she says.
The school's policy is to include its special needs children in as many activities as possible, such as PE, music and swimming. Two specials needs pupils sit on the school council, and another is an eco-school representative.
"Any success, large or small, is a cause for celebration. But this autumn one of our children will be going on to the comprehensive school as a mainstream pupil.
"That gave everyone here a great sense of achievement," says Mrs Muir.
Out of hours, she describes herself as a taxi service for her two teenage children, Jade, 16, and Matthew, 13.