I recently started with World of Warcraft and I now hit level 90. The only way I currently earn valor points is doing LFR (Looking For Raid, the group finder for raids). I know that you get them for doing daily quests, defeating bosses in heroic instances and raids, are there any other ways to get valor points? And what's the fastest way to reach the weekly valor-point-cap?
I'm going to suggest two methods that are by far the fastest.
Buy Deeds of Valor. This is the quickest method if you're already farming the Timeless Isle for Lesser Charms of Good Fortune in order to get you're weekly allowance of 3 Warforged Seals since you're probably also earning Timeless Coins at the same time. If you're sitting on more than 3000 coins, it will take you only as long as you running to Mistweaver Ai and purchasing them from her.
Run Heroic Scenarios. Find 2 friends and/or randoms in /trade and queue up. They're extremely fast to complete. I play a resto druid primarily, so I look for 2 DPS when running them. Having at least 1 tank or healer is helpful, but the final group composition isn't terribly important (just don't stand in fire), and there's no queue time once you've assembled your 3-person group. Some of the scenarios include NPC's that can also heal you and none of the mobs you kill drop loot, so the 3 person group can move from pack to pack pretty quickly. But speaking from experience, a healer will allow you to jump right into the larger groups of mobs and just AoE everything down. Be mindful of the bonus objectives, as they're timed events that can be completed for an extra 30 Valor.
Some thoughts: I'd probably avoid random heroic dungeons. They're not worth as much as heroic scenarios, and you'll probably be spending a fair amount of time in a queue waiting for the group to be formed. I tend to only do 1 random heroic dungeon since the first one is worth 80 Valor, but only if I can't find people interested in running a heroic scenario. However, as I mention above, I'm a resto druid so I don't have to sit in long queue times like DPS characters need to.
Since it sounds like you're freshly level 90, keep raiding because you could probably use the upgrades. Be mindful to how much Valor raiding is worth, and then supplement that with Heroic Scenarios or Deeds of Valor as appropriate. If you're starting to max out the LFR upgrades, start looking for Flex raids. You'll get higher iLevel versions of the gear that's in LFR, while still earning the Valor from boss kills. When you've cleared out all 4 SoO raids, finish off your weekly Valor earnings with Heroic Scenarios.
Wowhead has a good post on Valor points and all the locations to currently collect them. Link below:
In Terms of the quickest way to collect valor, it all depends on the playstyle, My personal experience with valor grinding is with a group of friends doing heroics which I found gave 80 for the first heroic of the day and 40 thereafter achieving a valor count of 200. (This does not count extra bonus, such as boss kills and such). If you can find a group of people decicated to farming challenge modes on the other hand this can give a reasonable amount of valor per challenge (If you finish them within the bracket times)
Bronze awards: 125 Valor Silver awards: 150 Valor Gold awards: 165 Valor
So as you can see, grinding out the challenge modes could potentially be the quickest way (As each dungeon should be within the time bracket that is given within game) but they are by no means the easiest.