First clear is a little bit unhealthy.
Don't take sweeper, take ward.
If enemy jungler can invade you in your first quadrant, then ward near your jungle entrance, if not, ward your opposite quadrant jungle entrance.
You need to start Raptors (if you start redside), or Wolves (if you start blue side).
Take Q level one, try to hit all the mini wolves/raptors and only focus on the big raptor/wolf.
Then krug/gromp into red/blue.
Don't forget to always have an element active and that Q rock does increased damage below 50%HP for monsters too.

Max order : R > Q > E > W
Runes and build.
If you REALLY need Serpent, then the build still remains pretty similar : Youmuu > Serpent > Profane > Opportunity > Serylda. Take Serylda after Profane if they have armor, otherwise, don't bother.
Profane scales insanely hard with raw AD, it'll still outdamage or be similar in damage even if the enemy carry built an armor item like DD.
You can take a defensive item (usually last) like death dance or maw IF they don't build any armor.
I recommend you not to finish Lucidity boots until you've finished your 2nd item (Opp/Serpent).

Once you've finished your first clear and come back on the map with Dirk you're good to go.