You know the skill sequence... Youre a carry join the fight shortly after it has allrdy begun with Flash or E. Target and use your W on as many champs as posible your and enemies or just simply target enemies AD carry to slow his AS and increse yours. THe enemy is most likely gonna target you for killing 1st avoid it by useing E or Flash depends on what have you used before. You need alot of farming. Allways kill the enemy carry 1st then kill AP champs after kill the rest.
IMPORTANT if the enemy has a feed suport allways go for him 1st cus he will save the carry or some1 else.
Try haveing buffs on you red and blue with pots offcourse

Same tactic as AD just in this case youre useing more E and W insted of Q. You will fail if you fail with your R. You need farm. Get blue as much as you can. Pots offcourse.

Same as AD and AP. Strugle your way to the enemy carry and kill it. Youre reling on your AS your passive and W. You will probably have 2.500 which is 10 hits in 4 secs plus spells equals around 3.9k damage I tested it 2.1 on a tank with 250 AR and 150 MR. You probably wont have that much kills but you will have more asists than the suport cus of the Spark. Try allways haveing buffs on yourself red and blue and pots offcourse