When I was tought technical drawing way back in uni days it was all 3rd angle projection drawn in pencil on a proper drawing board with fancy rulers that moved along parallel lines. All had to conform to British Standards for layout and content. There is a symbol for 1st and 3rd angle which is a truncated cone on its side and end so you can see how the part is rotated when switching views.

Nowadays the CAD creates the 3 views automatically from a solid model but I still try and keep to the main standards for dimensioning and highlighting parts of the drawing. I also tend to include an isometric view in the corner as this is so easy with CAD and can add to the clarity and avoid annoying mistakes when machining!

But if it is a part that I've drawn on a piece of paper for me to quickly make then it's just whatever works to get the thing made.