On your way up the mountain to go see the graybeards, you’re going to face a lot of obstacles.  The terrain, wolves, a typically-huge frostweb spider if you’re unlucky or it’s night time, an occasionally unclear path (hint- look ahead for stairs and rock stacks)....

Probably the greatest of these is the frost troll.  For those unwilling to /kill or otherwise essentially cheat their way past it, this thing is a heck of a fight given that you’re probably level 12 or 13 at best, unless you’ve spent considerable time mucking about doing side quests.  The troll is hugely durable, heals fairly quickly, and deals out blows you would usually associate with bandit leaders hauling around large two-handed swords.  It attempts to ambush you in or just after a brief ravine you pass through as you follow the path of the 7000 Steps, so it’s not hard to predict at least.

There are two main factors in whether or not you can successfully defeat the troll.  The first is your housecarl- or other follower.

You probably have Lydia as your follower right now.  This is a very good thing- since she wears heavy armor and uses a shield when she’s equipped to match her skills, she’s got very strong defenses.  This gives you a lot of time to try and unload into the troll while it’s distracted.  If, for some reason, you haven’t been having Lydia travel with you, you should use the quick travel option to go back and get her and then return to Ivarstead at the base of the steps.  Alternately, you could get a different follower, assuming you’ve got access to one- but a heavy armor sword-and-board warrior like Lydia is your best bet here, since you need a tank to give you time to beat on the troll.

The other factor is the situation.  If you’re lucky, the troll’s pathing will get mucked up and it’ll get stuck behind the stack of stones next to the shrine in the area where it appears.  Otherwise, you’re going to have to find a way to get a tactical advantage- the troll has stamina like you wouldn’t believe and can run around all day following you while you tire yourself out dashing ahead and then turning to barrage it with arrows or magic.  You definitely don’t have the raw toughness yet to take it face on without a huge stockpile of healing potions and food, either.  Try to find some rocks or something it can’t run over, and shift position so it’s constantly either trying to barge through them or run around, which it’s not nearly as fast at.

Either way, you should stand off to the side and attack from range if you have a good ranged attack ability (Destruction spells or skill with a bow) while the troll attacks your follower.  If you’ve specialized enough to have a targeted heal as a spellcaster, you can use that to keep your follower alive long enough to bring the thing down with a bit of an investment in mana restoration.  Keep in mind that unless you kill them yourself, your follower will only stop to take a breather instead of dying, so aim carefully but take advantage.  When your follower drops to one knee, you’re up- you need to fight as defensively as possible or the troll will gut you, no question about it.  It’s much easier to stick it out running in circles or protecting yourself with spells and shield until your follower gets back on their feet and draws the thing’s attention again than it is to try and face it down.  This will be alleviated in later fights with trolls by having a higher level.

The frost troll is a good introduction to fighting defensively, which you’ll need to do with some later fights, and it’s also a good lesson on the use of your terrain and tactics to beat an enemy you simply haven’t got the raw power to deal with.