What works for me: prototyping tables in Excel. Which is a grandiose way of saying: sketching them! Show a few rows for Table A, and how they connect to rows

What works for me: prototyping tables in Excel. Which is a grandiose way of saying: sketching them! Show a few rows for Table A, and how they connect to rows in Table B. Connect keys using colour coding, e.g. Table A's PK, and its FK in Table B, are both a certain shade of blue. This can quickly yield a sense of whether the model "feels right". Are copies of data showing up? Are there any situations which can't be represented? What happens over time - if a row in Table A gets replaced/superseded, how does that affect other tables? Side benefit - knowledge sharing. It's a nice medium for sharing with team mates and other colleagues for a really rapid share of info and design.