Having explored the range of coloured media available to me, I would say that watercolour pencils and coloured pencils lend themselves more to very detailed work. This is because you have a lot of control and a large range of colour with coloured pencils; you can mix the colours by hatching and they can also be rubbed out to a degree - allowing for correction of error. The watercolour pencils can enable also be mixed by overlaying one on another. They can also become washes of colour and tone when a smooth effect is needed- though as yet I haven't done a project where I have used them and then added water. Coloured pencils can also be used in addition to other media eg pastel, to add definition and impression of texture. However I feel that using coloured pencils can inhibit the freer type of expression that say oil pastels allow - just by their very nature of being hard and having to apply them in a fine and systematic way.
I think using ink fine-liners at the end of a drawing can add a strong but still delicate definition if needed.
I think that oil pastels are the medium that lends itself to more expressive work. The colours are vibrant, they can only be applied in a bold manner, though as I decided to explore in my final work there is scope to introduce detail into work by scraping off the oil pastel. However they could be used where fine detailed work is required.
