Now, you are truly worthy of the power of the world's greatest Hero. For starters, the strain of One for All is now dramatically lessened, to the point where, even with a completely average physique, you could harness post-injury All Might's level of enhancement without any backlash or damage, and that limit only goes up as your body gets better.
Secondly, you now have access to a particular trick similar to the big blonde himself: With a bit of exertion and concentration, you can 'puff up' your body into a massive, ripped caricature of your ordinary state. This isn't just for show or disguise, either; while in this form, you actually do get stronger - not to the same absurd degree as you look, mind, but still by a significant margin, which certainly helps with drawing out more strength from the Quirk. Do be careful not to lose focus and drop this form at a critical time, though.
Thirdly, One for All's link between its users, past and present, is enhanced as well, becoming a two-way road: Any former users, including you should you pass on the torch, will always have access to a small fraction of One for All's power, as well as all of its bearer's Quirks (and other genetic abnormalities). Furthermore, One for All no longer needs the sharing of genetic material such as blood to be passed on, only requiring either physical contact for new holders, or merely intent for previous holders, in case one needs to return it for whatever reason.
Lastly, and perhaps most importantly, the definition of the 'power' that One for All now stockpiles has become significantly more loose, to your benefit: Exploiting this new vagueness, you can harness its power for more than just as a physical enhancer, allowing feats such as enhancing additional aspects of yourself like senses and reflexes, tapping into a stockpile of stamina and vitality, and even emitting searing heat and electricity.
(Note: One for All may now potentially awaken Quirks in those without the requisite genetics, such as out-of-setting bearers. Potential quirks will usually be semi-random, determined by a mix of personality, background, and possibly species, should they be non-human)