Okay, so currently I'm level 7 and I've only killed one dragon so far (that one dragon that you kill with the Whiterun army and Jarl's housecarl). SO now I have one shout, the unrelenting force one, and I want to get some more. I've encountered about five dragons my entire time playing, to which I've been killed by every single one except for once, which I ran away from after jumping off a mountain. They always seem to just kick my rump so bad, and I'm wondering if there are any tips anyone can give me to help. Should I just wait to level up more or is there a stage in the main quest where dragons are easier to kill?

Any suggestions whatsoever are much appreciated.

Dragons often do the most dps when they are breathing fire/frost at you, you can counter this my shield-slamming his head which makes him stop.
also using a shout at his head has the same effect. if you're not the melee guy I would say hide behind a rock when he breathes fire/frost and shoot when he's doing something else (like eating an npc)
later ingame you can easily kill a dragon by simple hacking at his head and slamming him.

EDIT: to the guy under me.
why are you using a bow with dwarfen armor? if you got dwarfen armor you might as well use your melee seeing you probaly didn't upgrade your ranged attack with it.

I'm now level 13 with full superior dwarven set, and dragons also still kick my butt. The best chance you have is if there's multiple people involved. For example, the first randomly spawned dragon I killed was when he attacked the outskirts of whiterun. He focused on the guards quite a bit which allowed me to get proper ranged damage on him.

As for tips to fighting them, first of all have some good means of ranged damage, and start dealing it when he's hovering or down on the ground. It's ridiculously hard (usually) to hit him when he's flying. Use that time to heal up. Once he's down on the ground, don't attack him head on. Either move to his side and start whacking him from there, or run for cover immediately. Once he's grounded, you can often attack him from a safe distance.

Really melee works? I tried melee and got owned. I have beaten one dragon by shooting dozens of arrows at it while it was fighting three bears.

The only other one I've seen got one-shotted by a giant after a few arrows were shot by my companion

What I like to do is get the dragon to land, and while it spits fire at me I hide behind a pillar or tree, when it stops I shoot him with my bow.
If the dragon stays on the ground I kill him with my dual wield.

That way has never let me down before. ^-^

If you're a Nord, killing Dragons that use frost breath is really easy due to your 50% frost resistance. I believe Dunmer have a fire resistance as well, so that might be helpful too. You can also try and enchant equipment to give you higher fire resistance/frost resistance/etc. (Or find/buy it)

If you're playing as a Mage get the Dual Casting and Impact perks on the Destruction tree ASAP. You can use the stagger to interrupt their breath attacks.

Get fire/frost resistance and try to FLANK em from a distance.

Frost dragon vs Dwarven boots of frost supression and Nord' 50% frost resitance = immune to frost breath.

+ Overcharged Fireballs = WIN. (Not to mention a 100% mana regen mask and Arch Mage robes.)

Avoid their breath when they are flying, when the hover or land on building to attack you (with fire/frost breath) use something like firebolt (or flames if they are close enough) to deal some damage, and take cover. When they land, I usually use unrelenting force to stun them then take my dwarven axe and attack their head. Heal often.

J use stealth bows and cover. I also like to send in my flame autorough(SP) to keep it distracted.

Yes it works, killed something like 8 or so dragons so far with my two-hander, dual wielding might be trickier.
You can either sprint around it to try and dodge the flame/bite, but if it isn't too high level you can just run straight up to it, bash it in the face when it starts doing it's breath attack, block it's bite and just stab it in the nose

So, I'm a 2handed weapons guy with full heavy armour, but still I never got the inclination to attack their head. Probably has to do with one particularly nasty incident when a dragon ate me.

Heh, I'm already finding dragon battles kind of repetitive. Its gotten to the point where I lead the dragon to an area with other people or my favorite, the giants to help me out. The dungeon bosses are the ones really kicking my a**. But for dragon, I'm an archer and one handed so pretty self explanatory. Shoot when its in the air, melee on ground, shout if my health gets low to buy me some time. Its generally a quicker battle when I do get some aid, because I can fire and swing away while the dragon isnt directly attacking me.

And forgot to mention as others are saying, hiding behind a rock is excellent defense. Sometimes, kind of cheap, but when the dragon cant fly anymore, if its behind a large rock it may not come towards you if you are also behind a rock further away. It will just keep shouting at you, but the rock in front of it, and the one in front of you blocks most of its shout. When this does happen, I fire arrows away and watch my archer skill increase.

I've figured the hiding behind a rock method out myself as well, but it still burns me, even when I hide behind it. Really odd, I suppose it's some sort of small bug.