On this page I'm going to focus on naming trump in the second round. In this round, your seating position has a lot to do with that suit you should call. Here is a set of guidelines that should be followed. The first seat should try to call next, second seat should call reverse next, third seat would call next, and the dealer calls reverse next. While these guidelines are not absolute, it takes a much stronger hand to achieve success when they are not followed.
Remembering what card was turned-down is helpful. An ace turned means the king is now boss. A suit turned means there is one less card in that suit, thus a greater chance of being trumped. It could also mean the dealer is void in that suit. The 'next' suit also has one less card. Avoid leading an ace in either of these suits for the first lead.
Remember: There are seven potential trump in any hand. In most hands seven trump will be in play. Occasionally the kitty may hold one or two trump possibly but rarely three. A hallmark of the top players is that they always count trump. There is no better way to determine where the power cards may lay.
In the second round, this becomes the top position for naming trump. Consider calling next from here; many points are made with only one trump and a green ace. As you're not putting a trump in the dealer's hand and you have the first lead, this is the strongest position to make a lone call from.
This is where the reverse next call comes into play. Reverse next is when your partner turns down one color and you bid in the opposite color. The accepted standard for a reverse next call is a minimum of a king - nine plus an off-suit ace. Many new players do not take advantage of this call and miss out on many potential points.
If you have to choose between two suits, favor a call in next. Second round calls from 3rd have a better chance of success. This is due to the fact that up to now everyone has passed. The cards are more likely to be distributed evenly
Again, the reverse next call is your best option. It is possible your partner had help but didn't want to chance calling. When playing 'stick the dealer' and you must choose between two suits, reverse next will normally be the best call. It is doubtful that anyone has a very strong hand. When you do hold a strong hand, this may be a good time to try a lone. If the rules of the game allow you to deal again and you hold all junk, think about passing. Chances are you will get better cards on the next deal.