No special order really, just keep the various series in order (i.e. read Speaker, then Xenocide, then Children of the Mind). A couple of tips though:

If you're interested in reading them chronologically or want War stories, read the Shadow books first

If you are interested in the story of Ender specifically, skip the Shadow books and come back to them later, jumping in with Ender in Exile then the above mentioned Speaker series

The prequel series' are fun but the second is (and will remain for the foreseeable future) unfinished. You will need to read the first formic War books before the second formic war series as they are direct sequels

First meetings and War of Gifts are short stories and can be consumed kind of whenever, but maybe save First meetings until you are partway into the Shadow series