How familiar are you with Linux? I recommend lubuntu over xubuntu as it is much more lightweight, at the cost of being more barebones. Also look for guides to make a zram drive for your swap.
The biggest drain on resources tends to be web browsing and writes to disk, so try to minimize these.
I am in a similar position with a 32bit hp laptop, but I think I will try to experiments with a cli-only machine, and go with Debian.