For the longer time limit (10 and above), you really do have time to check your proportions every step of the way. One simple way to do that is to compare arbitrary angles that you make up. Like what angle does the end of the left hand make to the top of the head... etc.
For experienced artists, they usually get it right the first time, but if you're starting out, chances are the proportions or placement will be off. So get the big shapes right first and the relationships between them right. This is one of the things you can spend time on after the initial basic construction. In my own longer figure drawings, I will usually find something slightly off and correct it before moving on to the details.
After a while, it becomes second nature to measure these arbitrary angles and it becomes easier and easier to get the main proportions and placement right. Oh I forgot to mention that there are a few typical lines that you want to take note of.
- Line/angle between the two feet (where the figure is located in "space")
- Line between the two shoulders
- Angle and tilt of the head
- Relationship between the hip and the upper body (twisting, bending or stretching)