Write more. All the time. See what your thoughts look like on paper. Writing by hand conditions fine motor control. This can help with everything from improving synapse connections to properly fingering your partner to orgasm.
Read better. Learn to read a text deeply and thoroughly. Ideally, spend large amounts of time with novels published before 1998. Modern literature is bunk. Balance this with some vapid, trashy novels every now and again (to humanize.
‘Critical thinking’ mostly means being critical of your own thoughts. Why do you believe what you believe? Are you sure that’s the right/ best way about it?