What are the detailed differences between gram positive and gram negative bacteria.?

Gram-positive bacteria
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Gram-positive Bacillus anthracis bacteria (purple rods) in cerebrospinal fluid sample. The other cells are white blood cellsGram-positive bacteria are those that are stained dark blue or violet by Gram staining. This is in contrast to Gram-negative bacteria, which cannot retain the crystal violet stain, instead taking up the counterstain (safranin or fuchsin) and appearing red or pink. Gram-positive organisms are able to retain the crystal violet stain because of the high amount of peptidoglycan in the cell wall. Gram-positive cell walls typically lack the outer membrane found in Gram-negative bacteria.

When treated as a clade, the term "Posibacteria" is sometimes used.[1]

Gram-negative bacteria
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Gram-negative Pseudomonas aeruginosa bacteria (pink-red rods).Gram-negative bacteria are those bacteria that do not retain crystal violet dye in the Gram staining protocol.[1] In a Gram stain test, a counterstain (commonly safranin) is added after the crystal violet, coloring all Gram-negative bacteria with a red or pink color. The test itself is useful in classifying two distinct types of bacteria based on the structural differences of their cell walls. On the other hand, Gram-positive bacteria will retain the crystal violet dye when washed in a decolorizing solution.

Many species of Gram-negative bacteria are pathogenic, meaning that they can cause disease in a host organism. This pathogenic capability is usually associated with certain components of Gram-negative cell walls, in particular the lipopolysaccharide (also known as LPS or endotoxin) layer.[1] In humans, LPS triggers an innate immune response characterized by cytokine production and immune system activation. Inflammation is a common result of cytokine (from the Greek cyto=cell, kinesis=movement) production, which can also produce host toxicity.

When treated as a clade, the term "negibacteria" is sometimes used.[2]

In 1884, Hans Gram discovered that bacteria could be classified according to how they react to the crystal violet stain.

According to http://www.microbiologybytes.com/video/Gram.html:

"In Gram-positive bacteria, the purple crystal violet stain is trapped by the layer of peptidoglycan which forms the outer layer of the cell.

In Gram-negative bacteria, the outer membrane prevents the stain from reaching the peptidoglycan layer in the periplasm. The outer membrane is then permeabilized by acetone treatment, and the pink safranin counterstain is trapped by the peptidoglycan layer."

Most germs that can get you sick are gram negative.  Staph and strep are examples of gram positive bacteria.