Do's and Don'ts when developing First Project with Ignition?

Sure, one example is I used session properties to mirror a power chart so that if the user changes to a different view they don't lose their graph. Then I also added a context menu on any live points on the various screens so the operator can right click and add to chart. That way they can build charts without having to use the tag browser.

Worth understanding though there is a known bug that sometimes designer loses your session properties and if you save they disappear... so you have to be mindful of that bug.

That's why I use database persistence rather than session properties. That doesn't disappear when the user logs out, or logs in from a different device.

I use session.custom to handle "global" variables for stuff that we use across many customers. Stuff like Hand/Off/Auto - some customers prefer different words, so session.custom is where I store those lookups, and everywhere that needs them just refers there. So 1 spot to change and it affects all the buttons/statuses etc.