The drawing is an instruction
Somebody builds or machines from what you produce. That single fact is what
separates this from drawing on a computer.
An ambiguous dimension is a site query. A missing section reference is a phone
call. A wrong projection symbol is a mirrored part. Each of those costs somebody
time and occasionally material, and each is entirely avoidable by convention.
Layer discipline is the first thing checked
It is also the most common thing new draughtsmen get wrong.
Everything on layer zero, colours chosen by mood, lineweights that plot as
uniform grey. The geometry may be perfect and the drawing is still unusable to
the consultant who opens it. Anyone reviewing a test drawing sees this in four
seconds, and it decides a lot of hiring.
The software matters less than you think
Fluency in AutoCAD transfers to any other package in a few weeks. Conventions,
standards and judgement do not transfer from nowhere.
So when an advertisement names a package you do not know, apply anyway if your
drawing discipline is sound and say so. Employers who have hired badly before
understand this distinction very well.
The route out of drafting
Draughtsman is a good job and it can also be a floor rather than a career.
The way up is curiosity about the thing being drawn — why the section is cut
there, why that tolerance is tight, why the member is that size. People who ask
become designers within a few years. People who only execute find the work
narrowing around them.