Singing with enough compression?

I've always been a quiet singer, I couldn't ever figure out how my family sings so loud and my singing is always breathy and low, even when I strain to sing louder. I did the exercise on compression, which I think helped some, but whenever I sing I'm still not nearly as loud as my father, and although it doesn't sound breathy I can sometimes hear my breath coming out. My tone sounds kind of flat, not super round line Mr. Estabrooks or the singers I like to listen to. I also have to push a ton in order to hit notes for longer than a few seconds or when I sing even short phrases. I don't know if that's connected or not, but I just want to ask how I know if I'm singing with enough compression, and is it something I have to deliberately "turn on" every time I sinf or does it integrate with my normal singing voice with practice--in effect becoming my normal singing voice. Do I just do the "Guh" exercise over and over again and that will automatically improve compression when singing?

Some singers, due to their anatomy (and structure of their resonators), just have naturally louder voices! More important than volume is the quality of your tone. If you hear a lot of air leaking through, then compression exercises should help. Check out day 10 (cord compression) and day 15 (FAQ and troubleshooting). 

I'd also suggest you spend time vocalizing on SOVT's like lip trills, singing through a straw, and using an MM, NN, or NG. All of those configurations help line up your vocal folds properly, which is crucial to avoiding a breathy tone (ie: insufficient cord closure and air "leaking"). 

Training on any of those configurations (SOVT's) or compression helpers (initial G, B, or Y sound) are great; you can also incorporate some exercises that start with "training wheels" and then remove them. For example: sing the same pattern on GOOG, then GOO, then YOO (or something similar). 

Here are some more tips on increasing vocal power:

More power can come from increased compression (AKA vocal effort) and/or increased breath support/air resistance. The two go hand in hand, in my experience! 

Make sure you're adding power with increased bodily engagement, not increased "squeezing" or "pushing" from your throat. The gentle "pushing out" feeling in your low abdomen (of your normal “breath support”) can intensify to a little more of a "lean" or "slight grunt" feeling. The important word is “slight”: we do not want to squeeze or lock up the abdomen! 

The other thing you can play with is brighter, more forward resonance - that's not necessarily power, but it does sound louder and can be perceived as more powerful.