Ever since I installed Yosemite I have been irritated by the fact that there was no longer a new tabs button on the menu bar. I used that button all the time in Mountain Lion and missed it.
I happened to mention this issue to a friend and he gave me that look – you know the one that asks if you are wearing your stupid hat today. He said just use the plus sign on the far right of the window. It is located just above Spotlight.
Speaking of tabs in Yosemite, you can easily view all the open tabs on your screen at once. There is an icon you add to your Safari tool bar. Open View > Customize Toolbar and drag the icon you want to your tool bar.
I find this to be very helpful when I am researching or creating.