Some of you will already know this stuff, if that is you, do not bother being offended by these simple suggestions. But if you are new, and you're getting started now, read this.
Capture and Retain control of the neutral flags: This is one the most important things and first thing (after buying some basic equipment) you should do in a game. capturing flags gives you experience, as well it increases your war rank and each flag has it's own perk, whether it's extra experience, a more steady stream of gold, or control of a portal, you need the extra xp, income, control of whatever it is to win. Have you noticed the difference in levels and how it will effect the outcome of a battle one on one with another player? This is why you want experience. You want gold to afford priests, catapultsauri, good armor and helms, gloves, rings followers etc. these things tip the balance in your favor.
Teamwork: Work in groups, if you're alone and come toe to toe with more than one enemy, you're oftentimes screwed. Your death is more than just boring time for losers, it affects the outcome of the game. You do not accumulate experience or gold while dead, your level and your money effect your teammates in a direct way. If they need to cover your ass all the time, or if you can't effectively contribute (i.e. the other team is so much higher level than you that you can't fight them at all)or buy good enough items or citadel upgrades to keep your team in the game, then you're a liability, not an asset to your team.
Communicate: This is really basic, and a subset of teamwork. I really fault the gamemakers for not having voip built into the game in a simple way, but regardless of that. You need to communicate, "Their TB is hurt badly, now would be a good time to kill him"; "If you take down that tower, I can move the troops forward to the fortress"; yadda yadda. Super basic stuff. I need to go get mana is a major deal at times, communicate it to your teammates so they're not (Or you're not) hanging out on a limb when they were expecting you to be backing them up or whatever it is.
Retreat/Don't Die: This sounds almost bizarre it's so basic. I mentioned before some of the effects of dying, here are some others to give you some perspective, the enemy who kills you gains gold and experience for having killed you. Making their position better is bad mmmkay? The more they level up, the more resources they have, be it level, money, or war rank, the worse of you and your teammates are, retreat is a better option than fighting to the death, thinking you're just gambling a little bit and will probably win the fight. You're wrong (most of the time) don't gamble, retreat, drink potions, work in teams, whatever it is.
Remember as well that you're a part of the whole strategic action that will either win or lose the game. You're one of the more powerful pieces on the chessboard, don't take yourself off it.
Budget: This will be an entirely foreign concept to some of you, but you need to budget your money in game. You need to think about where you want your team to go, and where you want yourself to go, and how to get there with the resources you have, and think about it. A lot of people say that Citadel upgrades aren't worth it. I think it remains to be seen if that is true or not...however, the time spent respawning might be better spent fighting, earning experience quickly may help you with the fights you enter, stronger buildings with more firepower will help if you're trying to com back from a deficit. Right now I agree that this is an issue of game balance that is a bit of a mess. People win with very imbalanced approaches to the scenario you're playing out...and win, but I am sure the game makers intended for these things to be a factor, and at times they can be.
Don't fall behind: This game is one in which you can start to backslide easily, don't let that process begin, or it may be over more quickly than you want or think is fair. This is a game of king of the hill, the better you do staying on top of the hill early in the game, the better you're going to do later in the game (a large percentage of the time).
A lot of you are thinking, this is super basic, I don't need this, yadda yadda. If so, this post doesn't apply to you. But it's obvious some people do need to hear this super basic stuff. I hope this has helped some of you.