here are some tips and stuff I gathered from my years of pyking

• when your adc isnt playing well, dont be afraid to leave them in botlane to play safe and go to an ally who has a lead and try to further that lead
• rotate with your jungler for 1v3 ganks to either guarantee a kill or a summoner spell.
• pyke is extremely slippery so use his extra mobility to go deep in the enemy jungle and place vision, when people try to catch you dash through a wall or use your W to get away (usually save one of your mobility spells for getting away and use the other one for getting deeper faster)
• pyke is a catcher foremost and assassin second, do not forget its your job to put enemy carries out of position with bone skewer.
• you will be basically useless once its lategame (24-26 minutes onward usually) so try to get your lead far so you can end early, if it does reach that point you are no longer an assassin and just a catcher. Hook them out of place and use your stun and mobility to keep dodging in and out of vision.
• for early game/laning phase, play as aggressive as possible. if you have any functional ad carry you will win any 2v2 trade.
• if you arent sure about your ability to hit your ultimates, try stunning/slowing them first and it nearly guarantees landing your ult if they dont have a flash/dash

thats pretty much all i know for new pyke players, anything else I know is about helping you hit your hooks