In the first few lvls, you'll try to hold the lane as much as possible until lvl 3 if u can't out-trade your opponent/kill him.
Starting from lvl 3 you'll be able to win trades against most champions in toplane if the situation allows it( Minion Wave, ennemy's CDS, Tower etc..). The basic Combo on xin to optimize your damage output is the following : E-AA-Q1/W-Q2-Q3.However it is important to note the fact that you should never use your dash On champions like Riven,Darius,Renekton.. without seeing them use their own abilities in order to increase your chances of winning the trade. If the opponent runs Bone plating, proc it with your W at long distance to disable it without having to have a full trade
The W should be used right after the Q1 to cancel the animation and make it faster, afterwards finish the trade if u can, or back off with it.
If u want to dive your opponent with your R available do the following combo : Q1-Q2 on minions/tower, then Q3-R/W/Ironspike ignite on the opponent. This way the Q3 is directly cancelled by the R's animation,the R animation is also cancelled by the W's animation, and you finish with Ironspike to have maximum damages in a short amount of time with animation cancels. If the lane isn't killable play safe farm and see if you can roam.

After completing your Black cleaver you'll have to build tanky items in order to increase your survivability in fights. To accomplish that, build a Gargoyle stone plate against a team with various Damages in order to survive against their whole compo without being squishy against any particular damage type.
Against heavy AD, get a Death dance,and a dead man's plate for more aggresivity and engage potential, or frozen heart/randuin's omen for my defense. and against Heavy Ap get malmortius if you really want to increase your survivability, Or get Wit's End if u want to be even more oppressive on hit considering you have BC+Stride.Force of Nature is a good choice if the team is having a lot of magical poke, making you unstoppable to fulfill your role
Keep in mind your main goal is to protect your Adc, and not get into their backline, therefore make sure to be close to your adc in order to peel for him by attacking/slowing the ennemy engagers. After the selection of the right defensive options with boots and items, do your job and win the game!

Same as mid-game with even less margin of error considering you'll be a bit less powerful than before