'There's a special kind of nervousness that applies to performing at home," says the Scottish conductor Rory Macdonald, who makes an overdue debut with the Royal Scottish National Orchestra next week.

"How can there not be? I'll have friends, family, my old music teachers in the audience. They'll all be remembering me as a wee boy."

Macdonald, 34, has a career that sees him conducting in the major halls and opera houses around the world: Covent Garden, San Francisco Opera, the Vienna Konzerhaus, Beijing's National Centre for the Performing Arts. He isn't generally one to feel daunted, he says, but the Usher Hall and Glasgow Royal Concert Hall have personal history.

His formative musical experiences were on these stages as a violinist in the National Youth Orchestra of Scotland. "Playing Rachmaninov's Second Symphony when you're a teenager, full of passion and adrenalin ... You never forget those moments," he laughes. He also associates the Usher Hall with mind-expanding Edinburgh International Festival concerts: Claudio Abbado conducting Gurrelieder, Gunter Wand's Bruckner symphonies. "For me the Usher Hall is hallowed space. Most cities have one, but when I conduct in the hallowed spaces of London or Vienna - well, it's fantastically exciting, but different. They aren't my hallowed spaces."

Even if he feels added pressure for next week's performances of Elgar's Enigma Variations and a new choral work by Sally Beamish, he is determined not to get sidetracked. "I used to think I had to prove something," he says, "but I seem to be caring less and less about what people think. The more I focus on the work itself the less important those things become. When you start out you feel a lot of pressure for it to be amazing every time. I'm learning to accept that if I don't have a wonderful experience with one particular orchestra, it isn't the end of the world."

After spending an hour in Macdonald's company, such level-headedness comes as no surprise. Soft-spoken, impeccably polite, he chooses his words thoughtfully and doesn't seem bothered about crafting any particular image. In an industry full of flamboyant characters, he is notably demure.

We talk about the challenge of guest conducting, a blind dating game of which he has had plenty experience. Does he enjoy the huge amount of travel, the vast range of repertoire, the tricky psychology of winning over new orchestras? "Well ..." he takes a long breath, "a friend once described the first meeting between a conductor and an orchestra as being like dogs sniffing each other in the street. I'd say that's about right. There can certainly be wariness, but it usually subsides pretty quickly. The key thing for me is to be as well prepared as I possibly can."

He describes watching Mariss Jansons rehearse the Royal Concertgebouw Orchestra: Jansons noticed that one of the violin stands had a page turn in the wrong place and was surprised because he had gone through each part himself. "I can't claim that I always work at that level of detail," says Macdonald, "but I suppose that's the degree of preparation I'm aspiring to."

There are countless examples of orchestras finding the magic chemistry with a guest conductor and producing thrilling results; hopefully next week will be such a case. But it is clear enough that Macdonald is growing a little tired of the dating game and hankering after the stability and artistic depth that comes with a longer-term relationship. He hasn't yet been awarded a chief conductor post - hardly alarming given his age - but he has spent time in assistant positions with some of the world's great orchestras: Mark Elder and the Halle, Jansons and the mighty Concertgebouw, Antonio Pappano and the Royal Opera, Ivan Fischer and the Budapest Festival Orchestra. (The first time he worked on the Enigma Variations was in Budapest: "incredibly, they didn't know it," he says, "so in one rehearsal the entire orchestra just sat down and listened to Elgar's own recording of it. Fascinating to witness.")

He has learned his craft at the right hand of some of classical music's biggest players, and says he has taken different things from each of them. He acknowledges the "elastic way of phrasing" he has picked up from Pappano and Elder, two of the UK's leading opera conductors - "they really breathe with the music, and I hope I've developed in that direction." Being in the opera pit is an unbeatable training for young conductors, he says, because of the flexibility needed to handle an orchestra, chorus, cast of soloists, each with their own demands. "After that you approach the Enigma Variations in a whole new way, much more fluid."

There is an inescapable question for a successful young Scottish opera conductor keen to get his hands on a musical directorship. Would he consider the post at Scottish Opera, vacant since Emmanuel Joel-Hornak walked out on the beleaguered company more than a year ago?

Macdonald pauses, clearly aware that as a potential candidate he must tread carefully. "I haven't seen anything there for a while but I think they're doing a lot of good work as a company, and I'm looking forward to working with their orchestra after Christmas"- he's doing a one-off concert in Ayr on February 18.

He shifts tack a little. "One of my idols is Alexander Gibson [the great Scottish conductor who founded Scottish Opera in 1962]. I've got his score of Britten's Four Sea Interludes, though I've been too nervous to actually conduct from it! Growing up I went to pretty much everything the company put on. Hearing Jane Eaglen singing Die Walkure, all the big Wagner and Verdi - I learned so much from those performances. Like any musician who has grown up in Scotland I have a great affection for these institutions. You feel a sense of loyalty; you want these institutions to be healthy. It's a historically great company, and Scotland needs great opera."

A knack for diplomacy as well as a sizeable conducting talent: little wonder that Macdonald stands in such good favour with orchestras around the world. It's time we saw more of him at home.

Rory Macdonald conducts the RSNO at the Usher Hall on November 7 and the Glasgow Royal Concert Hall on November 8