I've been trying out a build that I find really effective you can try out. It's main goal is holding an area and taking out towers quickly. It's completely useless for killing enemy DGs (tho they'll die if they get cocky against you).
Basically grab Blood of The Fallen favor item (required or you won't have enough hp). You need a TON of mana, so you get all 4 helms, in this order. 4,2,3,1. The last one doesn't give much and you can skip it if you want (+8). Also grab some +armour/health if you need it. Even without any you should get around 5k hp by level 8.
Anyway, the general build is this... You want 3 things mainly. Towers, Structual Transfer and Shoulder Upgrades. Towers are your #1 damage against enemy DGs, shoulders against Regulus (he outranges towers). Do not engage enemy DGs without the help of towers, because you WILL die. Around level 7+, you need at least 4 towers to really beat enemy DGs. Also carry around a TP scroll at ALL times, because if you get 2-3 DGs attacking you, especially if one has an army, you're gonna die and you'll need to get out quick (wait till they've wasted stuns).
Basically you do 2 things the whole game. Camp flags with towers, and completely buttrape enemy towers with Structual Transfer. At level 7 with level 3 structual transfer, you can take TWO Towers of light SOLO. You have to hit and run though... Run in, structural transfer, run out.
So yeh, quick guide. Try it out.