Start following the relevant communities like old.reddit.com/r/proceduralgeneration/ and #procgen tag on social networks, read up on techniques others use. Commit to jams and community events such as PROCJAM and GENUARY.

Learn about perlin/simplex noise, Poisson disk sampling, packing algorithms, WFC, boids, inverse kinematics, SDFs.

Choose a style (2D, 3D, animation...) and from that start learning the relevant tool (Blender nodes, Houdini, Processing or something else). This is a decent start and it branches too much from here on, depending on your tastes.