When applying visual modeling, you can use various techniques:

• Identify the key perspectives: Focus on modeling the things that count. Few (if any) projects benefit from modeling the entire design to a great level of detail. Make sure that you understand why you are modeling something and who will benefit.
• Communicate key architectural perspectives: Even if you choose to model very little of your design, it is often advantageous to produce diagrams that communicate the key architectural aspects of the system. Conveying the "big picture" to the rest of the team helps them understand the overall approach and develop cohesive software. 
• Sketch the design: Not all models need to be detailed completely and presented in a software modeling tool. It is often perfectly acceptable (if not desirable) to produce hand-drawn sketches on paper or on a whiteboard when you are exploring and communicating the architecture and design with your team. You can use a digital camera or an electronic whiteboard to capture these diagrams and share them. For many small projects, this is often all you need. See http://www.agilemodeling.com/ for more information.
• Use a modeling tool as needed: If the team members are changing models throughout the project, sharing patterns/structure, debugging design, describing behavior, etc., then static photos or paper will become difficult to work with. The team may want to capture design in a software modeling tool. Other than communicating the design to the team, another benefit of a such a tool is the generation of structural code from the models. Many software development tools allow you to view the code as models, making it easier to comprehend static and dynamic aspects of a complex code base.
• Agree on a standard notation: In a team environment, it is important that others can understand your diagrams without much explanation. Choosing a standard notation enables others to quickly comprehend your diagrams without ambiguity. The Unified Modeling Language (UML) provides an industry-standard approach to software modeling and is an example of a widely understood notation.