Check in online at exactly t-24 to get the best possible seat. Then don’t print or download your boarding pass until the latest possible moment, this enables you to check back often to see if a better seat is available to move to. This does happen often in the hours leading up to boarding as people miss connections, upgrade themselves or move themselves to other seats they prefer.

I would actively avoid the advice to do everything you can to upgrade, if your mentality is that you have to get upgraded to be comfortable you are almost certainly going to be disappointed when you end up in the seat you booked. Try for an upgrade by all means but don’t set all your hopes on it.

Load up your tablet with entertainment, make the most of the fairly comfortable seat and free food and drink (feel free to ask for drinks outside of the service periods, they will be happy to get you one) and the 7 hours will literally fly by!