It's tedious, although it can be fun if you involve the family or have a friend over to help, but you need an accurate plan of the garden in order to draw up an accurate plan. So beg or borrow the longest measuring tape you can, find some small stakes you can use as markers, get out the clipboard and your pencil and go out into the garden again.
It is useful to have a rough outline to work to, so sketch out the garden first and then write the distance down as shown. For more detailed areas, draw an 'insert' style sketch on another page, making sure that you have the measurements that will enable you to relate this to the whole later.
Start from the house and measure the boundaries. Measure the diagonal distances as well as the length of each fence as these will enable you to pinpoint corner and, later, major features. This method is called 'triangulation' and it will prevent your plan looking lop-sided or skewed.
Measure the position of windows and doors in the house so that, later, you have an accurate idea of how house and garden relate. Mark and measure man-holes, electricity connections, sewage and storm drains. Moving out into the garden, measure and mark trees, driveways, swimming pools, steps and stairs. Anything that is large and/or likely to stay put in your scheme needs to be there.
Take your measurements inside, and, on the largest piece of paper you can find, begin to draw the plan. A3 paper is probably the smallest size that will enable you to draw the garden and work with the result. You will also need a pencil, clean eraser, a ruler with a good clean edge for drawing lines and a compass (borrow it from your children's maths set).
You will need to determine the scale of the drawing. Scales used are commonly 1:50 (where 1 cm = 0.5m), 1:100 or 1:200. You can draw the doors and windows taking the running measurements from the line D-E, and the other boundaries from the long measurements taken.
To determine the position of the tree put the point of your compass on A, with the marker-end extended to the measured length, and draw a small arc with the marker. Then place the point on C and repeat, using the CB measurement. Where the two arcs meet is the position of the tree. You can use this method (called "triangulation") to fix boundaries that do not meet at right-angles, drains and other objects or plants.
Once you have you master plan, you can use tracing paper to plan over it.
Make a copy and keep it in a safe place- accidents do happen!
Take your measurements inside, and, on the largest piece of paper you can find, begin to draw the plan. A3 paper is probably the smallest size that will enable you to draw the garden and work with the result. You will also need a pencil, clean eraser, a ruler with a good clean edge for drawing lines and a compass (borrow it from your children's maths set).