Best advice (if you can't find flights you can confirm on at time of ticketing) is to just wait it out.

UA's international ops are the one bright spot right now, so they're holding back as much F and C inventory as they can to try and sell it.

That being said, the upgrade percentages are still quite good (especially for 1Ks, but even 1Ps seem to be doing alright) and UA continues to release 1 or 2 seats as the Day of Flight approaches.