Are you monitoring your machine to check if it is not starving on cpu?
Re the queries, we have been using pgbadger to collect metrics about the usage of the dB and the slowest queries by type. This is helpful as it guides where you should put your efforts.
I've been waking up early (6AM) to learn Golang and Clojure. I't has been refreshing and I even fell more productive at work. (I work with Python most of the time).