The Blue Stash allows you keep a card for later use. You can place a card in it by tapping the Stash. Tap it again to take out the card. Placing a card in the Stash will shuffle you to your next card. Taking it out will replace the current top card, causing it to be shifted to the discard pile. You cannot place a card in the Stash if it is already occupied. If any cards are unknown, it is always better to have a card in the Stash, However if you can see what is remaining on the board, do not keep a useless card in the Stash. Use it to save something useful.
Combos
When given a choice between leaving a wild card on the board to be added to your total after finishing or using it to keep a good combo going, always use it for the combo. As long as it does not work against your main goal, picking up non-essential cards to lengthen your combos is usually a good idea.
Gold
Save gold to unlock the gates at the end of each world. If you have no gold, you will be forced to wait until a friend can help you.
Gold scarabs
When you pull certain cards (usually gold), a scarab will appear. Tap it as it quickly moves across to get the extra points.
Moves
Plan the order of each of your moves carefully in order to use as few cards as possible. Look through all of your cards to build the large possible combo sequence. The goal is to remove more cards with fewer draws.
Objectives
Always adapt your strategy to the current board's objectives. For example, if an objective is to clear the gold cards, focus on cards that must be cleared. Spending a number of cards to open up one wild card or earning points is a waste of time. If you need to remove a key block to get at a gold card, do so as soon as possible. You always need to earn a score of at least one-star in each board. For example, you may need to pull a blue card, make a sequence of a certain number, or keep five cards remaining in your deck. Get sequence requirements out of the way as soon as possible (removing a number of cards in a row without discarding). If you wait too long you will not have enough cards remaining on the board to complete it. Reveal any wild cards on the board, put a card in your Stash, and then proceed. Use wild cards to keep the combo going, and remember that you can use your stashed card without spoiling the combo.
Power-ups
Save your starting power-ups until you absolutely need them.
Wild cards
Save one or two wild cards until you are almost done. Use them to defend against a bad draw.
Blue Stash...