stick with it sickbo! as a video/computer game/sim with regards to how they've managed to mimic the playing of the real game - not just from a tennis point of view - from ANY sim, this really not only stands head and shoulders above anything i've experienced - it stands completely alone.
as you improve and learn different methods of play, you'll have matches that you start off playing thinking after a few points you can never win....and then through grit and stubborn defending and patience, turn it around - those games may seem rare, but you will play many of them as you improve!
i would suggest playing thru the single-player career mode, once you have a set-up you like - the truth/reality is you'll see a greater variety of play here than you will in the online matches....generally - and i'd recommend setting the CPU level to hardest difficulty.
you'll already have an idea of the online standard, but to 'bring it home', to be in with a shout of winning against most people on here, you're going to want to be beating the top CPU players comfortably (i tend to beat roddick/fed CPU (very hard) 6-0 6-0 with my girl character

)
You might try mixing it up - play some CPU matches, then some online etc - the styles are quite different, but over time and lots of it, you'll learn good techniques and styles of play - initially prob good to stick with a single style and get good with it - then try some different ones - major advantage to be able to mix your style up in a match - predictability is quickly spotted by these crazy guys, and the punishment comes soon after!
All in all, given the time committed and 'rewards' gained (even losing a hard-fought match can be a great experience with this game!?), i think TS3 may well be the best game i have ever played, and the singe-most impressive sporting simulation i've ever experienced, bar none.
If you ask Mr Djarvik (lol!) nicely, he's a veritable yoda of wisdom in just about all things TS3 (xbox and ps3 by god!) - apologies to all the other yodas...no offense!
Stick with it bro- not lightly do i say you absolutely will not regret it
