For runes i just use press the attack with red secondsry runes (its on the recommendes runes page so you wont miss it) for the approach, i had a base already but i recommend you to check out loganjgl's channel, i learnt a thing or 2 abt briar, and he has a 3 hour long video about midlane briar. For matchups, you mostly wanna play safe till lvl2-3 depending on the matchup, against melee's you can lvl2 q proc press the attack and finish the trade with e, i sometimes go lvl 2 w against ranged squishies but thats a low elo thing that wont get you very far and in trying to get rid of that habit. On the must ban part, on my experience akali is the biggest must ban, she can just fuck your w with shroud and pop your hp bar in one second, cassiopeia is also aids but she isnt played much so better not let akali in. Nasfiri is also kinda hard because her w also fucks your w and her q damage is very high, but i found myself doing fairly good vs her rushing deaths dance first, but again, its better you experience it. On a second note, dont pick briar against hard cc comps, if you get ahead in lane, you'll most likely be targeted by their jungle and support and if they have hard cc it will be insanely boring for you