Also Gwyddeligs response also applies to me:
On games above Monarch If I don't get trounced from the start, I end up in the middle of the score pack and can't be bothered finishing the game as I don't think I have a high chance of winning.
OR I do very well early mid game, get complacent then really mess up later (usually by ignoring an AI civ going for Culture win/or space race). Only to realise I needed to do something about the threat they pose about 5 turns too ago![]()
I'd encourage you to stick with it as a few canny tech trades can make a huge difference. Sid's Sushi can really rocket you forward. The Internet is your friend too. Don't bother too much with the score. As for not keeping a close enough I on the AI (as it were), I empathise entirely because it's quite tricky. I think I'm getting there though. Slowly.