There are many practices related to communing with the dead over many different cultures, the one or ones you choose to adhere to are largely up to you. As with all spells though there's no such thing as "simple" or "easy" not because they are difficult but simply because different people get on better with different spells and is one of the reasons I'd advise you to actually look into adapting practices to your own purpose unless you're wanting to follow a specific path or tradition.
As for common components of such a spell it's typically considered good practice to open a circle before any magical workings but especially when dealing with any form of spiritual entity as it gives you control over what you allow into the circle, thus giving you a higher degree of what entities you encounter and helps keep away the evil entities paganfanatic mentioned. I would also strongly recommend being familiar with at least one banishing method so that you have a backup plan in case things do go wrong. As for the best time of year most cultures agree that now is a pretty darn good one, late October and early November are considered to be the times of the year when the spiritual and physical worlds are "closest together" with a peak on Samhain. Ingredients vary wildly between cultures however if you're looking to contact a particular spirit then I would recommend using something familiar to them to help attract their attention, it could be one of their belongings, a favorite food, particularly if there's something special to the two of you then that can be particularly helpful to help focus your intent and draw them in.
As you may have gathered many prefer not to work with spiritual entities, with the exception of deities, as they do carry some degree of risk. Personally though I do not see this as reason for not doing it, simply reason to be prepared to do it, read around on the subject, get some ideas, learn what might go wrong and how to fix things if it does.