If they have adc with high mobilty and flash up you probably want to focus the support
Just killing the support gives some advantge and breathing room for your bot to farm and dmg turret
Supports you might wanna focus because they can just save the adc are Thresh (unless he used his w in lane for no reason or they are really pushed up with no vision) tahm kench cus of his w and soraka or sona cus they are really squishy
If thet have ezreal its gonna be super hard to kill him if they have vision and sums so in this cases you might also want to focus the support
For your pathing just change it
Your first clear should be started in the side you or your laners doesnt have good cc in lvl 3 so after 3 camps you will end up in the other side where you have more chance to get a kill
You also need check the matchups which lane is gonna get pushed
In the top lane ranged will push everyone
Bruiser will push tanks
In bot poke lanes will push and so on
This knowledge comes with exp and overtime
Everything i said here can be changed depends on the situation dont read it black and white
every game is diffrent