Where many young designers and architects stumble is in how to draw the ideas they have such that a client not only understands what it is proposed, but also approves it. Such approvals are key to moving a project ahead.
And when all approved, one needs to draw it such that the contractor and his team can build it.
In order to design space one needs to be able to represent it and in order to represent it, one needs a pretty clear set of skills.
1. The most important has nothing to do with creativity, but math. Specifically, descriptive geometry. This will allow you to draw objects, spaces, anything really such that they can be put together thru construction.
Imagine a tailor measuring a customer, then transferring the pattern onto the fabric and tracing white chalk lines on wool, then cutting, then sewing. The final garment has no seams that bulk, has no unwanted holes or uneven edging where evenness was intended.

Space is built the same way. Seams need to fit tight together, openings and cuts need to be well proportioned and well placed. The design pattern needs to be drawn onto paper, explained, such that it can be constructed.
2. The next has also to do with math, specifically arithmetics as it applies to ergonomics and regulated standards.
Desk height, closet depth, bed length, room and window sizing, passage ways, area of floor space required in front of a sink, adequate elbow room at the table. All such numbers need to not only be memorized, but known to such extent that variations can quickly be assessed and the right and final number selected.
There are hundreds of numbers that then need to merge in hundreds of combinations with adjacent numbers and standards such that they all work in unison within the physical boundaries of the available suite, property or lot.
3.The third skill, is having a “great hand” or excellent drafting-software knowledge.
A writer needs to know how to write otherwise he is just a story-teller. A designer needs to be able to draw what he imagines, otherwise he’s just a “creative mind”.
4.And finally the fourth, is knowing what you can and cannot do, how things go together and how you can detail your imagined space so that it is practical and it “makes sense”.