You need to understand your business first. Define your activites and find what is the exact definition of your business.  For example I do book writing and also do some checking work.  I am a Accountant as my most of activities are related to bookkeeping.

How many credit card you carry will depends upon the need of a person and various type of credit cards. It differs from a person to person

The role of internal audit is to provide independent assurance that an organisation’s risk management, governance and internal control processes are operating effectively. A baseline definition of internal auditing provides a starting point for understanding the roles and responsibilities of internal audit function.

“Internal auditing is an independent, objective assurance and consulting activity designed to add value and improve an organisation’s operations. It helps an organisation accomplish its objectives by bringing a systematic, disciplined approach to evaluate and improve the effectiveness of risk management, control, and governance processes.”

Major roles and responsibilities of internal audit function are summarised as below:

• evaluates and provides reasonable assurance that risk management, control, and governance systems are functioning as intended and will enable the organisation’s objectives and goals to be met
• reports risk management issues and internal controls deficiencies identified directly to the audit committee and provides recommendations for improving the organisation’s operations, in terms of both efficient and effective performance
• evaluates information security and associated risk exposures
• evaluates regulatory compliance program with consultation from legal counsel
• evaluates the organisation’s readiness in case of business interruption
• maintains open communication with management and the audit committee
• teams with other internal and external resources as appropriate
• engages in continuous education and staff development
• provides support to the company’s anti-fraud programs.

Source : http://www.deloitte.com/view/en_cn/cn/services/corgov/ic/iarr/index.htm

There are lot of requirement by various bank and credit company. However some common requirements are as below:

• You must have steady income to qualify for a payday loan.
• You must be able to show a verifiable source of recurring income payments
• Checking account information (account must be in your name)
• ID number (You must meet minimum age requirements, 18 in most states)
• Checkbook, debit card, or banking account information

The amount of risk or liability covered for an individual or entity by way of insurance services. Insurance coverage is issued by an insurer in the event of an unforeseen or unwanted occurrences. There are general different types of insurance coverage, such as auto or life or more exotic forms such as hole-in-one insurance. Source

Credit utilization ratio is an important component of consumer creditscores.  It’s simply your total credit card balances divided by your total credit card limits.

Gross profit ratio is  Gross profit divided by Sales . Gross profit  difference between revenue and the cost of producing goods or services sold.
The formula then becomes:

Sales – Direct materials
________________________________
Sales

Income statement and balance sheet are part of annual accounts of the company. Income from Income statement carried to balance sheet.

You can get the best rates only if you have good credit history and good cash resources. Rest all depends upon many factors like property to mortgages, location etc

Internal audit is get done by directories or management of the company where as externals audit is get done by shareholders or tax authority or bankers etc.