Way back in 2005, Kaplan was using a 12TEN mnemonic for Data Sufficiency, to help teachers help students memorise the meaning behind the Data Sufficiency answer choices.
12TEN is still a handy way to memorise those answer choices, which do not change from question to question. Quick recap:
Control the meaning behind the DS answer choices. That is the first step of a solid Data Sufficiency workflow - and the single biggest factor affecting DS performance. Workflow is like the pit crew in a Formula 1 race. An unstable workflow means missed steps, errors in judgment, and a need to repeat steps.
The first and most serious mistake is to mix the premisses. The two premisses or assumptions of a DS question should be considered individually, one by one, and combined together only in the final step, in cases where neither premiss is sufficient on its own.
Third step, stabilise your workflow. Check out the implications of Fact 1, henceforth termed F1. Is F1 enough, or not enough? Decide. Do not bounce down to Fact 2, or F2. A solid test taker can bounce around - even should. But make sure you are one of those, and in the meantime stay humble and work from F1 to F2, without fail. Build the habit. Otherwise you are at worst Toast, and at best Progress Long Delayed. Every Data Sufficiency question is set up to tempt you and delude you into blending your assumptions. The two facts, Fact 1 and Fact 2, or F1 and F2, are two totally utterly independent facts. Looking at the one means ignoring the other. Do it.