Tips for playing better
In brief
These tips are player habits, not rules: they always depend on the cards you can't see. The only obligations are those of playing the cards.
Bid or pass
The Jack and the nine of trump are the two strongest and most valuable cards. With one of the two, along with other trumps and an Ace on the side, bidding is often reasonable. With neither, bidding is risky: if the defense finishes ahead, it scores the whole deal.
Think of your partner: they also have 8 cards, and their hand counts as much as yours.
Counting trumps
There are 8 trumps in the deck. Count the ones that have been played: when none are left with the opponents, your master cards in the other suits can no longer be trumped.
Aiming for the last trick
The last trick is worth 10 extra points. Keeping a master card, or a trump, for the end can make the difference in a close deal, especially when the gap comes down to a few points.
Defending
On defense, when your partner is winning the trick, you can put a card that scores points on it, like a ten or an Ace of another suit. When an opponent is winning it, keep your high cards for a trick your side can win.