There are a few important carpentry skills which need to be mastered in order to set out and structure wood. Even if you cut the wrong side of the pencil line, it can comprimise the overal structure and will mean the thickness of the blade will be too short.
You should never work with blunt tools. This will make your lines not straight. If you want a good finish then its imporatant to keep razor sharp blades. All kinds of things like Chisels, planes and especially saws need to be sharp.
If you would like to take a course in Carpentry at a furniture school, there are many places you can go to in the UK. Here is one school: http://williamsandcleal.co.uk/
