There are a few choices.
First, there is a standard -- more or less -- set of private morning and evening prayers. The Jordanville Prayer has them in a fairly full version according to the Russian usage but the Greek usage, while shorter, is nonetheless very similar.
Alternatively, one could pray the daily offices -- most likely in an abbreviated format and there have been many abbreviated formats published -- matins and vespers, together with a set of bedtime prayers/compline.
A popular Orthodox devotion is, of course, the Jesus prayer. Some devout Orthodox pray this with the use of a chotki, or fabric prayer rope to help them focus. I would say that this is probably the most popular Orthodox "devotion".
Another practice that is not strictly devotional is to venerate the icons daily -- there are numerous Orthodox who do this. Also some Orthodox light candles or burn incense while they are at prayer or praying the Jesus Prayer in order to help focus.
Having said all of that, there are many Orthodox who don't pray very much at all (as in any other religious group), even among the church-going Orthodox. It is an issue with us as it is with anyone else.