That is for sure one good way to learn bit by bit. You can also try to establish contact to the community (if there is an existing one) and ask for useful tips. There might also be guides on SRC or elsewhere.
This may not be the best way but a very reliable way i have learned to speedrun games. You should practice each individual part of the speedrun and make sure you can keep the run alive even if you mess up by creating a backup route for longer runs. Try to become consistent with the parts of the runs and dont reset the run too many times if your a beginner. I also highly recommenced getting livesplit so you can keep track of the pace that you are on in runs and what you mess up on overall.
@Cappey6 a good starting game is Deepest Sword on steam. Free game, speedruns are short and it's pretty easy to learn.
thats all he does. you see him on the forums once a month to bump question threads by repeating someones answer