If you post some photos people might be able to ID some plants for you, then you just need to watch out for bulbs coming up and some perennials that die back almost totally.
If you possibly can ask the previous owner for information on what is planted, and their pruning regime e.g. for roses which can vary a lot the country. Also useful to know is the soil type (acidity and whether it is sandy or clay etc.), whether there have been any pests/weeds that you need to keep on top of, and whether any of the plants are tender. If they are keen gardeners they wouldn't mind passing on this information, and it would be so useful to have.
I have this mini-book, RHS Gardening Month by Month, it's useful for telling you what jobs to do for the time of year. Don't pay too much for it as it's only very small. One of the most important things about gardening is the rhythm of it. It's all about doing the right thing at the right time of year or in the right weather, pruning at the right time and planting at at the right time.