Abyss is a resource management game and success comes down to properly managing these resources which include:

• Cards in hand
• More higher numbered cards of different colors = more lords you can buy
• Card color flexibility is especially important when the court refreshes - you want to maximize your chances of taking advantage of the new lord pool
• Explored 4 and 5 cost cards should almost always be purchased while 2 and 1 almost never. 3s are a toss-up depending on how many pearls each player has and how useful it is building toward the current lords in court
• When spending cards, try to use either all high or all low number cards. Using one high number card with low numbered cards means a missed opportunity to affiliate extra points
• Saving high numbered cards to auto-affiliate at the end of the game is perfectly viable
• Cards in council
• The council is perhaps the most novel aspect of Abyss and by extension the hardest to build intuition on
• When cards are already in council exploring becomes a worse option as you risk a council stack becoming a more appealing option for your opponent's next turn
• Choosing to take council cards rather than explore has many important implications:
  • Your opponent does not have the opportunity to buy a card - you can lock down a lord purchase by getting the final cards from council
  • Barring lord powers, you can only gain pearls by exploring. This can lead to a give and take where players alternate who is exploring
  • Generally speaking it is better to not be the one exploring because it gives the opponent first dibs at every card
• Pearls
  • Pearls are not worth any points so as the game goes on they should be used more and more liberally
  • When your opponent has no pearls, exploring becomes much more appealing
  • Do not underestimate the value in spending pearls for buying lords. Purchasing a mono-color lord with pearls and a 4 or 5 card is very appealing as you can then affiliate that card
  • Spending a pearl to add a lord to court is very rarely a good decision but can come up
• Lords
• Active (key) lord powers can drastically warp the progression of a game. An exhaustive list is outside the scope of this guide
• Some lord powers with others in interesting ways. Learning all the interactions can only come from playing games
• Do not forget that getting a third key disables all of your keyed lords
• Points
• Like many similar games, the only resource that matters at the end is points
• Points come from:
  • Lords
    • Key lords are generally better early, point lords are better late. Though it's important to consider that not all lords are created equal
  • Locations
    • Depending on early key lord hits, it may be beneficial to delay your first location as much as possible. This has the added benefit of making a location choice working with as much information as possible
    • Generally speaking if none of the already revealed locations are worth more than about 10 points, you should reveal 4 locations. The added options for you far outweigh those for your opponent as you're often looking for the same locations anyway
  • Affiliated Allies
    • You should be looking to score around 20 points off affiliated allies. Plan your card and lord purchases well to affiliate high value allies
  • Monster Tokens
    • Do not underestimate Monster Tokens. In general whenever the monster track is at 2, you should fight it and take 2 tokens. Expected point value 6 is much better than a card