The first and most important thing to consider is what time of year it is. There are two reasons for this - firstly, you’ll want to use ingredients that are fresh and easily available. And secondly, you’ll want to serve the kind of seasonal food that people will feel like eating.
Take care to avoid using the same ingredients and flavours in more than one course. Repetition just ends up dulling the palate - and produces a boring meal, no matter how well it’s cooked. The same principle applies to colour and shape - remember, courses that look the same aren't especially inviting or satisfying.
It's important to let your meal build in a logical way. For instance, a very heavy starter will overwhelm your main course. So be sure to think carefully about how each course will affect the other courses in your menu.
So…seasonality, contrast and balance. Simple principles, but really important to keep in mind when you’re putting your menu together.