Good science
What makes good (legitimate) science?
How does new evidence become science? How can "peripheral" fields join mainline science? As we all know, many fields (e.g homeopathy, chiropractic, creationism, etc) claim to be science, but are rejected by mainline science. How could they become recognized science?

Basically 6 criteria:
1- Employ natural mechanisms - in no case has a non-natural explanation been scientifically useful

2- Employ scientifically recognized mechanisms

3- Be free of dubious assumptions

4- Have experimental support, preferably from several approaches

5- Have the evidence peer reviewed by the scientific community

6- Have the evidence serve as the basis for further studies which are also accepted by the scientific community
Scientific databases define science. Science Citation Index is especially useful because it not only includes the bulk of recognized scientific literature, but shows connections among scientific papers. These connections define useful science. Useful science relies on existing scientific publications and serves as a basis for further scientific publications.

The scientific community is crucial. It's skeptical as well as educationally and culturally diverse. The nature of the community prevents cults from gaining hold. New disciplines bear the burden of convincing the scientific community.

Some interesting examples:

Polywater

In the 1960s a "new form of water" was discovered. "Polywater" appeared only in fine capillaries. Its properties differed substantially from normal water, excited great interest, and stimulated many experimental and theoretical publications. Polywater was hypothetically dangerous. Perhaps contact with normal water (e.g., the ocean) could convert normal water to polywater. Ultimately fine capillaries proved ideal vessels for dissolving silicates (from glass). Reference to polywater quickly disappeared from scientific literature.

Plate tectonics

Early in the century it was recognized that eastern and western hemispheres had been joined and then split apart. The science community was dubious of "continental drift" for lack of a mechanism. Geological similarities in corresponding regions of continents offered few geological insights. Discovery of sea floor spreading brought plate tectonics into mainline geology.

Critical thinking in science, Sound science

Why science is so hard to believe