Hi msirchia,
A good way to attack the Logical Reasoning stimuli is to read through the entire stimulus, then look over it again for keywords used to denote a conclusion (So, Then, Thus, Therefore, etc.). Once the conclusion is identified, then you can work backwards to identify which statement(s) support that conclusion.
For example, here is the stimulus from Question #8, Section 3, June 2007 LSAT:
Advertisement: Fabric-Soft leaves clothes soft and
fluffy, and its fresh scent is a delight. We
conducted a test using over 100 consumers to
prove Fabric-Soft is best. Each consumer was
given one towel washed with Fabric-Soft and one
towel washed without it. Ninety-nine percent of
the consumers preferred the Fabric-Soft towel. So
Fabric-Soft is the most effective fabric softener
available.
Reading through it, we can see that "so" begins the final statement, which then turns out to be the conclusion of the stimulus. This is the simplest structure, but many questions' stimuli will be similar. Then looking at what statements support that conclusion, the three sentences preceding the conclusion describe the survey from which the conclusion is derived, making them the premises upon which the conclusion relies.
The next question, #9, is a bit trickier:
Naturalist: The recent claims that the Tasmanian tiger is
not extinct are false. The Tasmanian tiger’s
natural habitat was taken over by sheep farming
decades ago, resulting in the animal’s systematic
elimination from the area. Since then naturalists
working in the region have discovered no hard
evidence of its survival, such as carcasses or
tracks. In spite of alleged sightings of the animal,
the Tasmanian tiger no longer exists.
Here we don't have a strong signifier word/phrase, so we have to look at the stimulus more holistically and find the statement that answers "What point is the author ultimately trying to prove?" It's tempting to pick the final sentence, due to its placement in the stimulus as well as its conclusory nature. But in fact, it serves as an intermediate conclusion, supported by the two preceding sentences, which then goes on to support the actual conclusion, which is the first sentence.
I hope this helps somewhat, and let us know if you're still struggling with identifying premises and conclusions.