01 Always be ready
You never know when a great idea will come to you, or when you'll see something that will spark a train of thought. Carrying a sketchbook with you everywhere is as essential to a good illustrator as eating.
02 Utilise angles
Think carefully how the visual elements you're using 'bounce' the viewer's eye around a piece. You want the viewer to be drawn deeper into your image from the edges, rather than have their gaze led off the canvas. Utilise angles and shape to retain the viewer's gaze.
03 Going for gold
As an illustrator, it's crucial to have an appreciation of the golden ratio. Consider how 'divine proportions' can make compositions more aesthetically pleasing. Never ignore your instincts, but it can be interesting to see how close you are to this 'irrational mathematical constant'.
04 Less is more
Don't be afraid to take things out of your pieces if it helps distil its impact. Just as a film director might have to remove scenes they love in order to maintain the rhythm and arc of a movie, don't be afraid to delete layers or objects that you like, which have ended up being superfluous.
05 Take time to plan
However spontaneously ideas come to you, it's crucial to put the preparation time in before you actually knuckle down to your software weapon of choice. Sketch and research until the actual piece feels like second nature.
06 Choose colours wisely
A dramatic or iconic sketch can be compromised if your final version doesn't have a considered palette. By contrast, a well-chosen range can help make an image memorable, and is another way of drawing attention to key elements or establishing a mood.
07 Final touches
Sometimes it's the tiniest adjustments towards the end of the process that can bring an illustration together. Have a clear idea of what you want to achieve, but not to the point where you close your mind to exploring alternative ways to finish.
08 Know when to stop
This is one of the most important skills to develop over time. With a wealth of options available to you creatively, it can be hard to know when to down tools. Deadlines can help, of course, but be careful not to 'over-work' your pieces.
09 Work bigger than you need
If you work with bitmaps, it's a good idea to work on a larger scale than the brief actually requires. You never know when you might want a larger print for self-promotion purposes, or if you'll see a way to improve the composition.
10 This way up
Do whatever you can to view your illustrations in a fresh light. For instance, as you approach completion, turn your artwork 180 degrees and view it upside down. This enables you to examine your composition, colour and overall visual impact from a new perspective.