Which seats are served first in UCS?

Is there a set method for taking food & drink orders in UCS, i.e. start at the front on the LHS, and start at the back on RHS etc. I ask, as it wouldn't be the first time choices are gone/limited because other PAX have simply ordered already.
On this basis, is there a better seat selection for order-taking/service etc that has priority (in terms of the above)? I might change my current seat preference based on this for an upcoming trip.
On this basis, is there a better seat selection for order-taking/service etc that has priority (in terms of the above)? I might change my current seat preference based on this for an upcoming trip.