So, lets say I made some 3d text that I really liked. How would I go about copying the attributes of that text and pasting them to another text layer
Press the u key twice to reveal all of the modified properties of the text layer. Shift + click on each property you want to copy. You may not want to paste position, rotation or opacity properties. When you have everything you modified that you want to copy selected go to the Animation menu and choose Save Animation Preset. Give the preset a name, and make sure you save it in the default user presets folder so you can find it again. Now you can apply the settings to any text layer at any time.
I have more than 200 presets that I have created and saved in libraries and they knock hours if not days off a lot of my work.
To learn more type "save animation preset" in the search help filed at the top right corner of AE and do some studying. It's an incredibly powerful feature.