This List is a compilation from other posts on the wiki, my own personal experiences, or tips from other players.
As a supplement to http://pocket-knights.wikia.com/wiki/Player_Tips_%26_Tricks
Energy Crystals: Merge these into higher *s as needed for evolving heroes/gear
Dungeon Crystals: Merge these into higher *s as needed for evolving heroes/gear
Fusion Stones: Refine all unwanted level 1/XX heroes, you’ll need a lot of these to evolve your starter hero. Refine Stones: Refine all unwanted level 1/XX gear, you’ll need a lot of these to evolve your gear.
Summon Vouchers: Never buy these at full price (80 Diamonds). Ideally, buy them when you have the tower task ‘Bonus Surprise’- buy 1 Summon Voucher, get 1 free. Event Tower exchanges are also commonly available to spend 45-50 diamonds to get 5/10/15 of these at a reduced price, which isn’t bad either. Spending diamonds on Summon Vouchers is in most cases the ‘best’ option. With this tactic, you’ll also only want to summon heroes when they are either free (special 1/day, supreme 1/3 days) or when you have the tower task ‘Bonus Surprise’ – Supreme Summon x 10, get 25 summon vouchers. This way you can continue to rack up 5* Heroes more regularly and have 50 summon vouchers at the price of 12/13 instead of 50 each time.
Spades: Prioritize use of these on Dragas Treasure Maps 1st, then Treasure Maps.
Runes: Equip all 6 slots on all 5 of our heroes in your team with the highest level runes you have. Try to get all of them to the same level across the board. Replace them individually with the next level rune strategically (focusing on DEF/HP for Warriors, CRIT for Mages, & ATK for Hunters) until all are the same. For example, all runes are level 6 and are only replaced with level 7 on specific heroes based on class as they are available through combining. This is the ideal mathematic approach to rune level progress.
3★ Evolution Materials: Star Treasure Chests are another good source for these.
4★ Evolution Materials: Moon Treasure Chests are another good source for these.
5★ Evolution Materials: Combine ‘unneeded’ 5* materials into 6* materials.
6★ Evolution Materials: Save these for evolving your 6* heroes.
Booster Gems: Spend these on Spin Vouchers only (or on exchanges in Event Hall).
Courage Gems: Unless using to obtain a specific Courage Hero, spend these on Courage Treasure Chests in quantities of 20 – this usually will give you 1 Event Sun Treasure Chest
Pink Gems: These are a relatively easy way to obtain a 6* Warrior or Hunter (no Pink Gem Mages yet)
Royal Door Essence: In most cases, it is ideal to exchange for 6* Dungeon Crystals as these take a lot of 1-5* DCs and gold to make. If you are lacking in Evo Mats, utilize the following strategy. Using the Royal Door to Combine Evolution Materials If you are over Level 90 and only need 5★ and 6★ Evolution Material, it is no longer worth it to combine your 3★ and 4★ Materials. Instead it is worth it to wait until one of the royal door tasks is to 'Donate'. You can donate 3★ and 4★ Evo Materials for Essence and use the Essence to buy 5★ and 6★ Evo Materials, or 1-6★ Dungeon Crystals, and when spent on Evo Materials, it is far cheaper than the traditional combining.
60 3★ Material can make one 5★ Material 15 4★ Material can make one 5★ Material 900 3★ Material can make one 6★ Material 225 4★ Material can make one 6★ Material
Super Chest Monster: Don’t waste these, there’s a great ‘trick’ – see below. A T9, max level (85) super chest chest monster is worth 2,347,183 xp (base)... I got a x2 proc - 4,694,366 xp - the first time I used one, which took my Rathim from lvl 80 to lvl 95. NOTE – there seems to be a bug that only gives the bonus 2x EXP when fortifying a level 80+ Hero.
Star Treasure Chest: Spend ‘excess’ gold on these, open these in amounts of 1000 for a better chance of
Event Sun Treasure Chest: Primary source for 5*King’s Gear Pieces (3 pieces of a random gear)
Tokens: You can get 800 of these ‘free’ daily, also obtained from Guild Chests. Primary use is Auto Tower (VIP 5) & Auto Elite Dungeon (VIP 4), also used for Hero Set Out.
More to come…