Strategy:

 

The spot cards, non-face suit cards, are worth 1 point each. Because they have a low point value, they are excellent to use to bleed Tarocks from the other players, as long as you can continue to regain the lead.

If you have the 4 diamond spots, that leaves the 4 diamond face cards to the other 3 players. Let's say one player has the Jack & King, one player has the Queen, the other the Cavalier. You lead a diamond and the other players follow suit with King, Queen, Cavalier.

The next time you get the lead, lead another diamond: this draws out the Jack and bleeds a Tarock from each of the other players. Your third and fourth diamond will then bleed 3 Tarocks each.

Essentially, your 4 diamond spots will bleed 8 Tarocks and you can hope it was your partner who played the King! Whether or not, you're now in excellent position to trump everything else that comes your way!