I donít use anything for straight lines, except a clear ruler. No supports. Nothing turntable (interesting thought). I have an adjustable drafting table, but it is huge. I use a smaller desk for miniatures, smaller works. But I rarely work flat except if I am doing a big wash. Working flat will affect your perspective otherwise. Instead I use a smaller homemade drawing board that is basic and sturdy. My father in law made it in highschool for drafting class. I discovered it in his basement and cleaned it up. The angle is lovely for working at. It means I can do work in a smaller space. I love it.
The latest helpful device I decided I needed, and was recommended by others, is magnifying lenses in a head band....the kind jewellers would use. Or crafters. We will see if that can save the eye strain working so tiny.
I tape my work to my board lately, or if I need to turn it, I tape it to a sturdy good piece of cardboard. Overlap enough tape to hold the paper and not peel up (donít skimp- plan for this in paper size), and carefully choose a painterís tape you like. Some are worse than others. Sometimes I use a hairdryer. Sometimes, not. I work on 2 miniatures at a time. Especially if I am not using a hairdryer and wanting it to dry naturally. It means I can keep working and not lose the flow. It also means I wonít overwork an area I need to leave alone to dry. Hairdryers can be helpful, but some tape will leave all the sticky residue behind if you use a hairdryer. Or it will rip when pulled off. Also some frisket will stain and rip if left on too long or if heat from hairdryer is used. Some brands are bad for that. Anyways, if you tape to a good piece of cardboard cut to be a bit bigger, but not too much larger than your work(for ease of movement and reach), you just turn it as you go.
If you use a drawing board and need to use a big wash, and your work is taped to the board, just put something under the low side of the board to temporarily raise it. Like a book.
The impossible is only the untried...
True failure is never even trying...
Inevitably some attempts will end up in the trash.
Continue anyway. Perseverance can trump undeveloped, procrastinating, or fearful talent.