"Real" reverb vs. "Sears" reverb
Manuack, the short answer is that your question answers itself: the main reason that your plugins aren't giving you a "real sutdio" sound is because plugins are not real studio reverbs.
There are always exceptions to any general rule of thumb, but in general, software plugins are simply inferior to pro quality outboard gear. There are reasons why you can pay hundreds to thousands of dollars for a professional rack-mounted reverb (or to build a physical reverberation chamber) and you can get software plugins for under two hundred dollars down to free. It's not just because the cost to manufacture physical components is higher than the cost to duplicate software (though that admittedly is a part of it.) It's mostly because there is a difference in the quality of the results they produce.
The longer answer is that you can probably get better sound out of the plugin reverbs you have, but it will take some expirimentation to determine - for your tastes - which reverb settings (plate vs. hall, etc.) work best with which types of instruments, how much predelay and reverb to apply for how long, what the wet/dry signal mix should be for each application, etc.
The medium answer is that although there are no hard-and-fast rules, there are some general tips that can work as a starting point.
1.) Don't overdo the reverb. Often times, a just little can go a long way. Most of the dubious mixes I have heard (and created myself, I admit) where the reverb was a problem were because there was just too much reverb being applied. Back off the level and amount of reverb used, or increase the ration of dry signal to wet, and often times you find it to be much more pleasurable.
2.) Set the delay time to the track’s tempo for max depth. For shallower depth, set to tempo divisions. You can calculate delay times with this formula:
60,000/BPM = ¼ note delay in ms. For example if your frack is running at, say, 120 beats per minute, then you can calculate 60,000/120 = 500, meaning that a delay time of 500ms is equivalent to the length of a quarter note. 250ms would be the lengh of an eighth note, etc.
3.) On a mono reverb, Return the wet verb to the dry mono source at the same pan to strengthen the sound (esp. especially acoustic or vocal.) Return the wet at a different pan than the dry for an ambience effect.
4.) On a stereo reverb you can sometimes enhance the effect by slightly brightening one side and darkening the other side with just a little EQ.
There is a wole lot more to it all, but maybe those can get you started?
HTH,
G.