Get a soil test now. Once you know what you have now you will be able to determine what you need to add, For example if your soil is too acid then the winter is the best time to add ground limestone to correct.it and there are other amendments that can be added now that will build a store of essential elements and also amendments that can improve the texture--you can do a lot of things in the off season that will lead to a better season next year.If you live in the US contact your local extension service for soil test help,