A technical job is good so you can see how things work at floor level and you get to use the equipment in a real-world scenario. Get to see the implications that decisions you will make as a designer have on the people who'll be working with you.

As a sound designer you're constantly having to occupy a middle ground of being able to talk artistically with directors and being able to talk shop with technical people - quite often translating conceptual ideas into a practical reality. Get used to how the different stage, lighting and sound crews work and interact, and the role of a production manager; and learn how to talk to all of them.

Avoid the stereotypes - don't constantly wear a leatherman and maglite, speak to the director in artistic terms rather than in terms of overtime. Give the director the opportunity to be able to regard you as someone with a creative head on them, even though you’re doing a technical job.

There are a variety of ways of getting that first job, in fact getting work is something you need to work very actively at for the first few years - eventually a snowball effect will build up, whereby most shows will lead to another show, either by working with the same director again, in the same venue or through someone recommending you. But for the first few years you need to seek out work very actively, and develop your skills to be able to do further work.

You should get to know different aspects of the industry and get some idea of the type of work you'd like to do: are there specific companies or directors you'd like to work for, or venues.  Then get some industry experience - for example, a technical job or as a designer's assistant.