I take about a 90 minute nap when I first get in (9-ish?). Get up when the alarm clock goes off, play tourist a bit, eat, drink be merry and about midnight or 0100 I'm about ready to fall over dead. I sleep a solid 7 or 8 hours and then I'm golden for the flight back.
You really have to learn what works best for your body.
Like on the domestic side, I tried to stay up at late as possible here in CVG, then slept in as long as possible. That way I'll pretty much be alert until it's time for my break on the jet crossing the Atlantic.
I'm still in the experimental phase of figuring out what's best for me.
As a west coast "night owl". It's easy as pie because even when you're on arrival into Europe, my body still thinks it's "prime time to post in the lavatory" so I'm wide awake 90% of the leg without a problem. I'm naturally nocturnal, what can I say.
Plus, I drink far less coffee to stay alert than I did domestically. I think I might have only had a single cup this entire six day trip.