Required information

When creating information in Salesforce, there are 'required' pieces of information that must be included in the form. The table below gives you a list of required fields for some common objects in a standard Salesforce implementation:

Account: Name

Contact: Last Name

Lead: Last Name, Company

Campaign: Name

CampaignMember: (i.e. Adding a Contact to a Campaign): Contact ID, Event ID, Status

Event: Subject, Date, Time, Duration (usually defaults)

Task: Subject, Priority, Status

Opportunity: Name, Close Date, Stage

Case: Status (usually defaults to New), Origin

Solution: Solution Title

Product: Product Name

In terms of some common AppExchange applications, here is the required information for a few popular installed Salesforce Lab Apps:

Class Enrollment:
Class: Class Name
Enrollment: Class ID, Contact ID

Project/Issue Management:
Project: Project Number
Issue: Project ID

Recruiting Manager:
Candidate: Candidate Name:
Applicants: Applicant Name

I hope you find this useful. Don't forget, this includes the information you MUST include, you are likely to want to include much more than this...