Did you start your GLA yet? You can grab flash from there. You can also get provoke. Flash eats MP, which you don't have a lot of, so be conservative. Provoke uses neither TP nor MP, so it's nice to use in a situation like that, and then it's on cool down (CD) for 40 sec's. I've found that as a low level tank, you can use everything in the book, but if someone with item level 100 and an atma weapon is banging away, you're going to lose enmity (aggro). You can also get Savage Blade from your GLA class, and that has an enmity boost associated as well. As for your own strikes that maintain enmity, use Heavy Swing followed by Skull Sunder in a combo. I typically use a macro that sends a Tomahawk at the target I want as 1. I then run into the middle and flash, get to an edge and Overpower (maybe 2x's) and then start beating with heavy swing, skull sunder, and savage blade (in that order). If I lose aggro, I might try to pull it back, but not at the expense of kiting a mob around the room. If a DPS is running around like his hair is on fire, you might be fighting a losing battle trying to get where you can grab aggro while literally running in a circle.If the healer is smart and has aggro, they will bring the mob to you so you can overpower and flash. They can do this by running or using fluid aura to push them your way. Sometimes, it's a losing battle. You get EoS or Silene from a high level SCH, and you may as well just concentrate on beating that mob down when you've cleared everything else.
Things that are out of your control can be the level of the other folks, DPS who run ahead and try to tank for you, DPS who attack wrong targets and kite them around, and adds that pop up while you're trying to keep the giant monster in one place. I've only been tanking a little while, so I can only share what's worked and advice others have given me that's been tried and true.
And to agree with Nabian, flash is often overused but at lower levels, any little bit can help. I forgot to mention Internal Release and Convalescence. I haven't got Awareness or Mantra yet, I'm not leveled that far in the GLA or PUG yet. As soon as I have those, I will have a cool down macro for them as well.