Here are five things you should know when playing Spades.

#1 Counting Cards and Memorizing
Counting cards is the one key skill that will improve your game more than anything else. It will give you the know-how to figure out that the Jack your partner's holding will win you the game or that the two of Diamonds in your hand will cover your partner's nil.
After you understand how to count cards, you will need to learn to memorize the cards that other players play. Top-ranking Spades players remember who threw what in all 13 rounds.

You can get started by trying to remember the number of cards that haven't been played in each suit. Another great approach for beginners is to try to keep track of the important cards. For instance, if you're holding the Ace, King, and ten card of the Spades suit, keep track of the Queen and Jack cards to know when to use your ten.

Once you're able to remember which cards haven't been played and who played which cards, you will be able to recreate the deck in your mind and figure out who has which card.
Playing against an opponent that has learned to count and mastered memorizing will only help you get better. Studying another player's game is a great way to learn. Just remember that writing down the cards someone is playing is considered cheating. However, memorizing them is not cheating.

#2 Never Take Your Attention Off the Game
Paying attention to what cards are played is vital to learning to play the game. If you pay attention, you will always know what suit the opponents are in and can avoid giving the lead back to your opponents.
Furthermore, knowing what suit your partner is in will help you give the lead back to them when you're through with your run down.

Paying attention throughout the game will enable you to play tricks on your opponents. For instance, if you have the Queen, Ace, and five of Hearts, playing the Queen first could scare your opponents and discourage them from playing the King card since they'll know an Ace is waiting to take the trick.

#3 Bidding Mistakes
Getting the bidding right is vital since it sets you up for success (or failure). Here are some simple mistakes that you can avoid when bidding:

If you only have two Spades, take half a trick away from your estimation of how many you could win.

If you have fewer cards of the suit, someone else has more, and it's twice as likely that it is your opponents that have the cards.

If you have only one Spade card or don't have any at all, subtract one full trick from your estimation of how many you could win.

If you have a lead of over 100 points, bidding nil doesn't make sense and puts you at great risk of losing your lead.

Bidding past 500 points is not required unless your opponents are positioned to win. Let's say your hand has cards to win three tricks, and your score is 492. Bidding 1 is a good idea, granted your team is not at the risk of bagging out.
If your partner bids one, bidding 12 or 13 is not a good idea. Bidding "1" typically means that the player can win one trick and potentially a second trick. It's best to bid as if you need to help your partner win the one trick they bid for.

#4 Take Notes
When watching someone really good at the game, take note of who played which card in every round to break it down for yourself later. With these notes, you will be able to copy the player's game and understand how the player is thinking.
Counting cards and memorization are skills that take long periods to build. Taking notes is a great way to improve your game in a short time.

#5 Learn When Not to Break the Spades
If your opponents have a high bid and nil bid, and your team has a low bid, you must avoid breaking the Spades. The idea here is your opponent with the high bid should not start taking leads or take as few leads as possible. If the other opponent wins the nil bid, your team will fall behind by a hundred points.

Conclusion
The best tip any player will give you is to play more games and find a partner as interested in the game as you. If you remember the things discussed above, you'll be a step closer to being the ultimate card shark.

Playing Spades with friends isn't always possible. You can resort to playing Spades online to get some practice.