Possibly one of the most difficult things to do when you are drawing is to reflect on your own work. It is vital that anyone learning to draw learns to evaluate their own compositions. The style in which you draw or your approach are obviously influencing factors in the aesthetic of your image but, however you approach your project there should be an element of realism to your delivery if you have chosen to draw from life.
Constantly checking the still life (landscape etc) in front of you against the image appearing on your page is all part of realising a reality in your work. Even abstract work needs to have roots in reality to have a proper integrity.
Given that the ratio to looking at the still life set up to drawing is a minimum of 65/35 it can be easy to overlook small assumptions in your drawing. After all we all know what an egg/apple/flower etc look like don’t we?
However, the honesty you can give yourself when critically evaluating your work will make all the difference to its credibility. Also mistakes in compositional integrity create a strange jarring quality even if the viewer has not seen the original set out of objects.
Learning to see and more importantly correct your mistakes (however far on in the drawing you are) will pay dividends as you progress. It’s very hard to say to yourself, “no that is wrong I must alter it but the end result will bring you one step closer to a harmonious and believable composition.