This article lists a couple of Do's and Don'ts for beginner Tableau users.
Remove Keep Only and Exclude in your Tooltips
This option, in my experience, can confuse the user if they accidently select either of these buttons. I have received many a ping from users that get their workbook "stuck" and they don't know how to clear out the view. This feature is more of a hassle than a helper.
Go to your Tooltip Marks card menu and uncheck the following buttons to remove this option:
Remove Sort Controls
In the same line of thinking as the above suggestion, remove the automatic sort controls from your chart. You may not want your user to be able to sort the view by hovering over a column in the worksheet and accidently clicking this field.
To remove this feature, go to the Worksheet menu and deselect Show Sort Controls.
Remove Gridlines
Gridlines can create visual noise in a chart. To remove these, right-click on your worksheet and select Format. On the icons next to the Paint bucket (Format Headers and Format Lines menus), use these two buttons to select None for the Panes, Headers and other lines.
Removing the Title in an Axis
Right-click on your bottom or side axis and select Edit Axis. Simply delete the text in the Title field. You have to think, does the title really help your chart? It is a good practice to remove this detail as it does not add anything extra to your dashboard.
Abbreviate Your Months and Years
Beginner users usually don't know that they can abbreviate months with the Custom setting. On a chart, right-click and select Format on the Axis with the date. Select Custom from the Dates field drop-down. Enter MMM YY to get the abbreviated month and year for your axis.
Don't Use Default Color Palettes or Wild Color Choices
One way to show your clients you are a beginner is to go with the Default color palette. Additionally, try to use the Color Blind palette. Some developers use the Red Amber Green color scale which a lot of users cannot differentiate. I also recommend using a monochromatic color scale instead of the default color palette.
Don't Use Too Many Colors
Some users like to use Heatmaps and multiple stepped color choices. Do the middle colors help you to quickly differentiate metrics? Do these colors help you to quickly make a decision? You can move stepped colors down to 2 options instead of 5 etc. to quickly display negative and positive metrics.
Delete the Default Phone Layout
Sometimes you may not realize that this option is checked. In your Dashboard menu at the bottom deselect these two settings below if you wish to disable this option.
If you have a phone layout on your existing dashboard, click on the ellipsis to delete the phone layout.
Think of your Dashboard as a Grid or Rule of Thirds.
The upper left hand corner of your dashboard is prime real estate for any visuals. Beginner users can waste this space by putting a map into it. I made this mistake in this dashboard here. Put meaningful charts in this space instead.
The rule of thirds is a photography method that you can apply to dashboards. There is an article about it here.
Use Tableau Public for Inspiration
I have created an account in Tableau public and have more favorites than I do followers. There are so many creative people out there. I obtain so much inspiration from others in that site.
Do a Makeover Monday Challenge
Participate in at least one Makeover Monday challenge using Tableau Public software. It's free and helpful to see how other users approached the same challenge as you. It is also very helpful to watch the recap videos from Andy Kriebel. I guarantee you will learn something new from these challenges.