So you are starting a BI project, or doing some analysis or looking for patterns.
You may receive a Specification Document or after a couple of interviews with your customers/users (there will be a separate post on how to interview your future users and how to write a specification Document) you wrote a requirement document or perhaps you were asked a question that required some data mining or analysis.
The most important thing is to start getting to know the business, understand the processes related to the activity you are about to perform.
For example, you were asked to build a sales or a purchasing model, you should understand the process of sale, what is the indicator of sale closing, what document (is it an invoice or shipping doc)?
After you gathered all needed business information, you should know your data.
Is it flat files or data bases , the meaning of fields and relationship between different entities.
Of course if you received a source to target instruction and detailed specification document, you may save a lot of efforts, but still try to understand as much as possible in this scope of your project/activity to be more efficient and independent while investigating and developing
Feel free to contact me on any of those channels: