Landing a juggle in tekken is like landing a phat punish in any other fighting game. One or two juggles per round is pretty standard, as is any punish in other games.
Some things most people don't realize is that juggles in tekken come largely off mids and highs. Some come off lows, but for the most part those are slow to see and you can learn to block those when you become familiar with them. The quick lows don't really lead to ginormous damage, but rather to oki or minimal damage.
Pretty much in tekken, you can shut down options by -
1 - looking for bid damage lows, they're usually slow on startup so you can train yourself to see them.
2 - break throws, takes some practice but once you do you can guard those as well
3 - moving properly so you don't get smacked in your dashes
Once both players can shut those top 3 options down, then you get to intermediate tekken play where for the most part you fight standing and move right, so you don't get launched. From then on it's a footsie battle, and determining when you're opponent gets tired of eating ticky tack lows and doesn't want to take that damage anymore, once you've made a read on those two things then you've opened them up. Also if you make a read on a poke, you can always sidestep. Sidestep in tekken is pretty much teh same thing as a parry in 3s for the 2d dudes. You make a read on a button, and then punish the button with a universal counter.
BBBUUUUTTTT
Screw namco :/ I'd be a lot more hype for TTT2 if it wasn't going to be on consoles like 4 years later. A 1.5 year delayed console release for t6 pretty much destroyed the games tourney scene in the states, the game was damn near irrelevent the second the mlg circuit was over, and even until then it barely got attendance in most tournaments. As of now, it's pretty much dead. I'll enjoy TTT2 casually if it's ever released console, but there's no way I'll be exerting effort into a game that'll have a jacked up tourney scene stateside.