If you don't know your Coreopsis from your Cosmos or your Godetia from your Nicotiana then help is at hand! This quiz will help you recognize and identify popular garden annuals and at the same time provide some pointers about how best to grow them.
After you have read and researched a little you should dive in and mix together the plants that you think will make a pleasing combination. Never worry about making mistakes with mixed plantings - if things don't work out ideally then do what every other gardener does and blame the freakish weather! Have fun.