When I teach people to be full of themselves, their initial visceral reaction is the normal, "Whaaaa? That's not right!" The reaction of deprecating modesty is actually a script of devaluation.
I'm not talking about the boastful, egotistic, a**hole type of fullness but rather the expansiveness, unencumbered, natural, free, light type of fullness.
Another way to look at it, is to view all the stories and scripts that are not your true, soulful essence as things that take up your sovereign space on this earth.
You know, all that crap that people talk about....stuff from your childhood but also, the invisible undercurrent of ancestral patterns that people unwittingly play out like an Oscar winning actor as well as the weights from evolutionary adaptations around fear and scarcity (think about how most people treat money, for instance).
Rid of those things, you'll feel space immediately. Space for 100% of you to fill in.
To get there, it's not a defiant, 'GET OUTTA MY SPACE!!!," but rather, something as easy as looking at your life - that's the easiest and most accurate data point of what's filling your space. Gracefully, on your terms, you can look at the undercurrent of what's been created, subconsciously in your life, and find what things violate your magnetic north...all the stuff that annoys or pisses you off.
If you find anything there that's not yours, one thing that I teach clients is to translate that feeling or event or person into a metaphor (one of the languages of the subconscious and your soul) energy that represents the essence of what is so disagreeable to you. Giving it a vehicle to be seen releases its power. Then visualize what it is that you really want in the same metaphoric terms and naturally, that's going to expand - that's how your soul works, it's just waiting for a chance to expand, transmute what's not yours.
It's a beautiful, easy, and simple way to expand. There are other ways explained in the True Life Roadmap, and like the above exercise, it's meant to be easy and practical so ownership of your space is natural and not dependent on anything external to your life.
So, hashtag this: 100PctYou, baby!