When designing active filter for your project you will need software tools to help you get right component values as well as minimize time spent designing. Tool that will hel you automate this process is FilterLab from microchip.
FilterLab® is an innovative software tool that simplifies active filter design. Available at no cost, the FilterLab® active filter software design tool provides full schematic diagrams of the filter circuit with component values and displays the frequency response.

Often you will need to filter signal to adjust it for ADC measurement or remove noise from measured signal. Analog filters are right way to do this. Here is some basic information about analog filter design terms used when designing filters. Active filters give better performance since they can be adjusted not to attenuate signal.