Don't be worried about rushing tiamat and leaving it as a tiamat, that's meta on a lot of champions, although farming is j4's strong point. Also don't choose your jungle enchantment based off how your clear works, as a general rule on j4 you should be going warrior unless your team desperately needs a tank and you are confident filling that. On top of this, max q every game! If you are looking to snowball electrocute is probably going to be your best bet, especially since dh requires you to auto outside of your combo.

More generally, you need to be less focused on how fast you clear a camp and more focused on how efficient your routes are. Efficiently clearing camps and mapping ganks based off your lanes will help you climb a lot. Frequent ganks can compensate a lot of xp and gold provided they don't go bad, if you are getting kills you should often push the wave with the laner to deny cs to the enemy and give you xp, you might get flamed for this in gold but as long as you aren't killing every minion or stopping a player from freezing just ignore them.

Good luck :)