You won't go far wrong if you right click with the mouse on the page ,tab ,toolbar etc. to check out the options
learn a few keyboard shortcuts Alt, Alt + P , F2, Ctrl B, F4 , Ctrl D, F12 & of course F1 for help.
Right click on a page and drag down a little & Opera will ask you if you want to turn on mouse gestures you only need to learn 3 or 4 to really speed up browsing.
The first thing you should do on installing Opera is Shift F12 to bring up the appearance panel click on Panels & make sure the Show panel toggle at edge of window is ticked exit the appearance panel & click on the left of the screen to show the panels click again to close.
The main panel for most people is bookmarks then notes select some text on a page right click & copy to note (double clicking a note in the notes panel opens the page it came from in the current tab, it acts like a bookmark) the windows panel is very handy if you have lots of tabs open.
Open the Appearance Panel again & select skin, check find more skins & they appear in the panel it is very easy to download a skin & install it.
Check out the toolbar options placement & style, obviously the address bar is not suited to the sides of the screen. Same with the buttons you can drag & drop a copy from any toolbar onto any toolbar apart from the personal bar which is reserved for bookmarks.
With the status tool bar & address bar open try dragging the address field button from the address bar to the status bar. If the Appearance panel is closed you need to hold down the shift key first.
I recommend getting rid of the menu button the Alt key is better as all the options are underlined i.e. pressing Alt e is the quickest way to show the Appearance panel.
The usual way of removing a button is to right click it /Customize/remove from toolbar.
This works with the menu button as well but because it is a toolbar it reappears when you restart Opera . To remove the menu bar button Alt e to show the Appearance panel/ toolbars then click on the menu button & set its placement to off .
To get the menu button back it's Alt w to turn on the menu bar then File/show menu button.
If you have a bitorrent client that you use like utorrent you should type opera:config into the address bar goto Bittorent & make sure the enable button is unticked.
Most of the customization options in opera:config come under user prefs there is a long list but i advise caution especially as the help files are missing.
You might want to google opera custom buttons for more options as well.
Then it's Alt P for the preferences panel choose the startup type that suits your browsing habits & fill in the basic info in the forms for auto complete to work.
Once you've licked Opera into shape you should enable Opera Synchronization it's the button far left on the status bar called Opera Link or Alt S you'll have to set up an Opera page so you can log in from different computers.
It's worth doing even if you only ever use Opera at home. Your PC crashes & you are forced to reinstall Windows if you've synchronized with Opera reinstall Opera login & your bookmarks, notes, speed dial settings are restored it only takes a couple of minutes to arrange the toolbars to your liking.
One warning only use turbo mode if your connection is slow or you are trying to save bandwidth ( it might help in some countries to access sites that are normally restricted ? just a guess) and I find the Auto mode for Turbo to be patchy so I either have it on or disabled , if you have a fast connection it will slow you down. I love Turbo mode but you have to know when to use it.
Apologies if I've sent you into Information overload