Well if your really having trouble,you can always go down a diffriculty.But what works for me is to have lots of Razor girls to take down the leeches and build your booths(remember to double team!it takes less than 5 DT shots to take out a leech)
constantly build razor girls,and maybe a bassist or 2 and keep upgrading your stage
after you get every geyser on your side of the sea,you should just guard your end of the bridge until you can get a rock crusher.when you do,take out the drowning doom troops in the middle of the bridge with your bladehenge assault double team,itll completely destroy them.this leaves the towers open for your crusher
by this time,you should have 1-2 bassists,quite a few packs of girls and a rock crusher.this is enough for you to rush her stage,remember to use the face melter and bring it on home solos.if you take out all her troops on the bridge before hand,you shouldnt even need to rock block her.
if you think you should take out her booths before rushing,do so because this will guarantee your victory.remember to use the rock crusher's double team when attacking the towers.
this works for me every time on brutal diffriculty,but if it doesnt work for you maybe its just not your style.hope this helps!