Getting XP is very much random in this game. Your best shot is to built a XP-farm, and visit it daily, hoping that some of the events will proc.
I’ve separated XP-events into three categories by the rarity of their occurrence. The chance of an XP event triggering seems to have two separate cooldowns (judging from my own observations): one based on time, and another one based on amount of other XP events that occur to you.
This means that if you’re stuck not getting any XP, it might be a good idea to travel to various local resources and get XP from them, perform some more obscure XP-yielding tasks , as clearing rare ones can reset your other common events, or wait. You can find an incomplete list of them here: http://ringofbrodgar.com/wiki/Experience_Points
Here’s my list of farmable events based on their rarity.
Every 1-2 days:
Treading Grass. 100 xp, achieved by walking onto some grass.
Sowing Time. 150 xp, plant seeds.
Having a Seat. 75 xp, sit on a chair.
Heave-ho! 75 xp, lift an object.
Quenching Thirst. 75 xp, drink.
The Tables Have Turned. 75 xp, placing a lifted table.
New Land. 50 xp. Walk into different terrain.
Every 2-3 days.
Striking the Earth. 175 xp. Dig once.
Well Wishing. 100 xp. Use a well.
The Symbel. 150 xp. Get a stat lvl up.
Monster in the Cellar. 150 xp. Enter a cellar.
By Weeping Willows. 75 xp (boo!). Right-click on a Willow.
Familiar Face. 200 xp. Walk into the water.
Fashioned with Love . 125 xp. Craft anything.
In Golden Fields. 175 xp. Harver barley crop (stopped working for me).
Every 5-7 days.
Watercraft. 150 xp. Place a boat into the water (glad that’s fixed).
Roaring Fire. 250 xp. Light a fire.
Driving out the Darkness. 300 xp. Light a fire at night/cave.
Sensing the Beast. 100 xp. Load an animal into your minimap might only work with boar/deers).
Soot, Cogs & Fire. 300 xp. Open a lit smelter.
The Mother Lode. 250 xp. Mine a tile next to an ore vein (this one is kinda rare).
Drawing Blood. 150 xp. Butcher a corpse, probably with skin on (unrealiable).
Burying a corpse. 500 xp. Self-explainatory. Unconfirmed.
I should also mention that every Local Resource has a 100% chance of giving you 400 xp first time you see it. These events have a cooldown of up to 1 month (again, based on my expirience), so it's worth visiting them once in a blue moon. Same goes for the Nidbane and quest giver events.
With this knowledge, you can construct an area in a way that would get you the most chances of getting XP.
For example, here’s my town’s small XP farm. It covers 10 XP events, and has instructions written on signs. Of course, it lacks a well, a water tile and lit furnaces, so you can always make a better farm yourself.
