Begin with a working Ogre project. I suggest copying and pasting the project in the eclipse project sidebar.
Right click on the project and select "Properties"
Click the "Advanced Settings..."
Click the "C/C++ Build" drop-down on the left.
Click Environment
At the top of the "Tool Settings" tab, select "[All Configurations]" in "Configuration:". You may need to scroll up, to see it.
Add an environment variable with the "Add..." button.
NAME=BULLET_HOME VALUE=C:\GameDev\bullet
Edit the PATH environment variable so it now contains
NAME=PATH VALUE=C:\MinGW\bin;C:\GameDev\OgreSDK\bin;C:\GameDev\cegui;C:\GameDev\bullet
Click "Settings" under "C/C++ Build" on the left side of the window.
In the "Tool Settings" tab, click "Includes" under "GCC C++ Compiler"
Click the Add button icon (a document with a green plus sign on the right).
You will need to add the directories where the include files are for bullet and OgreBullet. You can type exactly what appears below. Eclipse will use the variable ${BULLET_HOME} here.
${BULLET_HOME}\include
${BULLET_HOME}\include\OgreBullet\Dynamics
${BULLET_HOME}\include\OgreBullet\Collisions
Click "Libraries" under "GCC C++ Linker". In the section "Libraries (-l)" add the following names:
BulletDynamics BulletCollision OgreBulletDynamics OgreBulletCollisions GIMPACTUtils ConvexDecomposition LinearMath
Add the library paths in the "Library search path (-L)" area.
${BULLET_HOME}\bin
${BULLET_HOME}\lib
Click "Ok".
When you first make your run configuration, switch to the Environment tab and add a variable called PATH containing the value:
C:\MinGW\bin;C:\GameDev\OgreSDK\bin;C:\GameDev\bullet\bin