The Original Sentences are:
It would be a better idea to show you my works.
A better idea would be to show you my works.
(The initial I think adds nothing but syntactic complexity to either sentence, so let's ignore it, OK?)
The Original Questions are:
How are they different?
Where is the emphasis in each of the two sentences?
(1) is easy. The two OS differ in that the first one has undergone a variety of the Extraposition transformation. That takes a sentence and rips it into pieces before reassembling it with a dummy pronoun subject, and the original subject on the other side of the verb phrase.
- To chop broccoli is his fondest dream.
- It is his fondest dream to chop broccoli.
- That he's smiling like that makes me nervous.
- It makes me nervous that he's smiling like that.
It's very common, especially with that-clauses and infinitive clauses as subjects.
(2) is not easy, at least as it's phrased, because it's not clear what is meant by emphasis, and what it might mean for this emphasis to be located at some point in the sentence. Emphasis has a number of meanings in English, but one of them has to do with syllable stress (The emphasis is on the second syllable in "bedraggled".)
However, if emphasis has anything to do with meaning, it's not anything that can be answered by syntax, because there's no meaning difference between two sentences related by a transformation. That's what "syntactic transformation" means.