Don't give up.
Even if you feel like you are a way off getting 3 stars on a particular level that you have played many times before, you should not click that X button and quit the level. If you do, you will lose a life. All you need to do is pass the level's criteria and you won't suffer this ignominy.
Use the pet delay.
When a pet is at the bottom of the board about to be set free it takes a few seconds before it actually disappears - this means the blocks stay in place for a while and allows you to make more block matches before the board adjusts to the lack of pets
Watch out for pets!
If you have a lot of pets to rescue on a particular level, try to avoid the screen dropping below The Pets
as this makes it very hard to pass the level.
Save your power-ups.
The power-ups that you are given during gameplay are very scarce and should be treated with the appropriate level of importance. If you have power-ups left over, don't just use them for the sake of it. They cost you points (when you bear in mind that if you remove blocks using actual clicks, you will earn more)
Don't waste Lives.
If you have friends gifting you lives, bear in mind that once you reach the limit of 5 Lives, any more will be a waste.
Use your power-ups.
OK, so this contradicts the tip above, but you basically want to use power-ups like the Column Blaster Booster if you get to the end of the board and have blocks left over. The idea should be to clear columns or lines, leaving blocks of the same color left over to complete the board.
Don't rush your decisions.
There's no reason to speed through a game - try to look a few moves ahead to avoid rushing into anything you might regret.
Focus on your goals.
Early on in the game you are told to try to match as many same-colored blocks as possible together. However, before long you are given more and more physical goals and objectives to complete - you need to pass these to be able to complete the level, so get used to learning what they are and prioritizing them.
Save The Pets.
gets you 1,000 points each, which can often make the difference when trying to beat that 3-star goal. The other clear bonus of doing this is that saving pets is usually a goal for most levels.
Spending your Coins.
You will undoubtedly get to a stage in Pet Rescue Saga where you have heaps of Coins piled up and nothing to do with them. At no stage do you have any opportunity to spend Coins, on anything except for Block Buster Boosters
. This is one of the oddities about Pet Rescue Saga.
Target blocks with your power-ups.
As has already been mentioned, you earn far more points for clearing blocks manually than when using power-ups. As a result, you should try to use power-ups only to target specific blocks which then bring groups of same-colored blocks into play, which you are then able to remove manually.