One of the trickiest aspects of embroidery to start with is knowing how to transfer a design onto fabric. There are a number of ways to do it, depending on the type and colour of fabric you are using and the complexity of your design.
Here are some methods:
If you are using a light coloured fabric that's quite thin you can trace your design through your fabric. You can use a pencil but if you want to be able to remove the lines easily the best is to use a wipe-off marker pen. These pens make light blue lines, which disappear with a small spray of water once you no longer need them to be on your fabric. You can simply trace the design from paper onto your fabric - to see the lines through the fabric it helps if you tape the paper and fabric onto a window or use a light box.
Iron-on pens like the Sublime Stitching fine-line pen are great for transferring designs onto darker fabric that cannot be traced through. For this method you need the reversed version of your design, printed onto paper. Then simply trace over the lines on your paper, taking care because the lines are not erasible. Using a hot dry iron, warm up your fabric first before putting the paper ink side down onto the fabric. Slowly iron over the top of the paper, being careful not to move the paper. I've found, depending on the fabric you use, that you can get 2-3 transfers from the same tracing. The lines created are fine enough to stitch over with 2 strands of embroidery thread. You can also use the heat transfer method with iron-on pencils, although your line won't be as fine or defined.
Carbon Transfer Paper
This method works well for light and dark fabrics - you just need to choose a colour of carbon paper that will show up on your fabric. The trick with this method is to make sure that your fabric is on a hard surface. Then place the carbon paper, powder side down, onto your fabric and the design over the top. Using a sharp pencil, biro or tracing stylus, trace over the design.
Sticky Fabri Solvy
Sticky Fabri Solvy is a printable, self adhesive stabiliser. You print or draw your design onto it then simply stitck it to your fabric and stitch over the top. When you've finished, put your fabric in cold water and the stabiliser disolves away completely. This method is particularly useful for intricate designs or when embroidering onto felt or other fabrics that are difficult to draw onto. Check beforehand that your fabric is OK to be submerged in water and that the threads you are using are run-proof (DMC embroidery threads are).
If your design is simple or if you're confident drawing you can free-hand draw onto your fabric. For light coloured fabric you can use a pencil (but the lines won't come off easily) or a wipe-off marker. For darker fabrics, a wash off white fine line marker works well - the white lines take a few moments to develop so don't be surprised if you can't see them straight away :)