Problem: People tend to forget that testing starts way before any code is written.
One of the common mistakes is to wait with test until running code is available. Some testers spend their time writing huge test plans, and a million test cases while waiting for some running code to test. Some might even do reviews of specifications, flowdiagrams etc. but still all of these activities require somebody else to deliver some test basics. Do not get me wrong here, cases and reviews are definitely worthy workproducts, but waiting around for someone else to deliver something to test is a waste.
Solution: Informal discussions for clarification, preferably BEFORE work is started.
Grab a cup of coffee, and go talk to people – Your project is full of people who all knows something about the product. I love this exercise, as it allows me to interact with project stakeholders and explore functionality in the making.
Easy?! Yes, but after a cup of coffee things changed. The new perspective was caused by a discussion on test scenarios that I executed earlier in the test environment. While looking for test data the developer found my scenarios and asked me if I could give some details on the business behind.