1.) Most obvious improvement is gear. Work towards getting tier bonus. Most SV hunters have either last season's tier set or this season's. You're working with 0 tier which puts you at a huge disadvantage. You also want to avoid pieces with mastery as much as possible. Focus on gear providing crit/haste over what you have now, and always Sim your character to see what items to work towards.
2.) Take Serpent Sting off of your bars. Looking at your normal Kazzara kill (since it's a purely ST boss) you casted Serpent Sting 9 times. Since you're talented into Viper's Venom, each Mongoose Bite has a 30% chance to apply/refresh the dot, along with your green bomb which will also apply it. Just doing your natural rotation ST rotation without casting Serpent Sting should have a very high uptime on your dot.
3.) Manage resources/buffs/debuffs more closely. It seems like you overcapped on Focus a few times in the fight. More Mongoose Bites, less Kill Commands. Try to avoid casting Kill Command when you will become focus capped. Over use of Kill Command is also overcapping your stacks of Tip of the Spear (Kill command increased the damage of your next Mongoose Bite, stacking 3 times.) This will probably be resolved with better focus management.
I'm not sure what the recommended talent build is for 0 set. It's not a bad idea to get used to your current talent build as you'll have S2 4 set eventually, but there may be other builds that could contribute more DPS in the meantime.
On a positive note, you do a good job consuming your Kill Shot procs in your CA window with a high uptime on boss!
Added some screenshots of talents I referred to as well as compared your focus to one of my longer Kazz kills.
Hope this helps!
main verge
flint nymph
