This response is just a little naive. It presumes that the peaks and dips you see on a response curve can be treated alike. Nothing could be further from the truth. The fact is that a room response is a simplification of a complex system of speaker and room dynamics interacting over space, time, and frequency. Some of those dips can be the result of resonance processes that are far more powerful than your sound equipment, and they are best left un-excited. Now this fact is truer, the larger and more complex your room becomes. For a small listening room, peaks and dips may be little different, and raising a peak may actually work. However, as the OP first said, this is a dangerous game, although it is only dangerous to sound quality, and most of the time it won't damage anything.It’s a tired myth that seems unwilling to die. See here for more detail.I was under the impression that a little low-end boost was needed with the THT to get to 20 Hz, althought I know that any boost is a dangerous game and it's best to tame the high than raise the lows.
So how do you know if you can boost the dips? Well if you have a dip, try to raise it 3 dB by boosting the filter 3 dB. If it responds, then fine, you are OK with that. If it doesn't respond, that is, if the dip moves, say only 1 dB to your 3 dB adjustment, then put the filter back, and let that one alone.
Wayne did warn against one kind of boost you shouldn't tackle- boosting a ported woofer below its port cutoff. This can damage the speaker because its not supported by any air coupling below port resonance. Raising that dip will damage your speaker. OK, now imagine your entire room is a port, coupling into heating ducts, or some other resonant column. Trying to raise that dip will start the walls of the ducts rattling, and do nothing for your sound quality, although it may shake out some dust.
Every peak and dip has a reason for being on your plot. You would do well to try to find the source of the peaks and dips before you try to correct them. Lacking this dedication, make small corrections and be sure your room is responding to your corrections before you add any more. Pathological problems can't be fixed with equalization, and should be understood so a workable fix can be addressed.