First things first: You need more land. This is because you have a lot of high costing spells and you're running two colors. at the very least with you're mana curve you need to be running 24 lands. Ditch the guildgates, they'll only slow you down with this deck. Include the shock lands and duel lands you have in you're maybe board. To fit the extra land in you can cut some of you're burn budget. Morgue Burst is far to expensive to hit from the grave, and if you're worried about losing you're beefies like Thundermaw Hellkite than i think you may want to read up on the Rakdos guild. Take out the Magmaquake as well because if you use it to it's full potential, it'll clear your board as well. Add in another Searing Spear because it is the most versatile burn in the format. you might also consider Murder as an option to add as well. Replace Mugging with something else, it's expensive, and it only does two damage. A nice 1 or 2 drop would fit well into the slot. You need alot more cheap creatures to hold out untill you get the bigger guys.