Sketch so lightly that you can barely see the pencil marks.
Don’t start drawing a tiny portion of your image.
Draw you enter outline first otherwise you can’t judge if the drawing is in proportion.
Don’t worry if everything doesn’t look right the first time.
This is why you drew lightly correct your drawing before you go any further.
Once you are happy with what you sketched fill in slightly darker lines.
You can use these lines to be more careful and correct the first lines. If you mess up, erase the first line. Don’t get too dark, or you won’t be able to completely erase the lines!