I have to second sitting in an exit row. Depending on when you go,I would suggest a light jacket just in case you need to warm up a bit. I'm usually doing TPAC flights (where the cabin is usually warmer than I would like).

What I do is I carry a portable USB fan (I can't find the model I use, but I got it at Walmart for $10+tax.... this one is similar, but not quite as compact as the one I have)...

https://www.walmart.ca/en/ip/royal-s.../6000193833295

When I'm feeling warm, I hand the fan off of something like the coat hook or off the edge of the seat in front of me (making sure I don't disturb them) and point the fan at myself. If it's still too warm (and you're not doing anything that requires the tray), use the fan and place a cup of ice in front of it. NOTE, the fan may annoy the passengers grouped with you so make sure you check with them as well. If you can get a whole row to yourself, this works exceedingly well.