Second trumpet players should always be a mirror of the first trumpet player. He or she defines every way that you should play. Unless you have a solo, remember that you are there to complement his or her playing, not to overpower him or her in a mixed brass ensemble.

If you are the section that was chosen to replace the woodwind parts in a transcription, try to "sound" like the section you are replacing. That does not mean that you should necessarily sound like a clarinet, but it means that you should play flowingly and bouncy, like a clarinet does at times.