I think you need more practice fighting. When you have a local advantage, do not let your opponent off by playing mild defensive moves, instead look for a strong attack. Examples from the game:

challenges B to fight or submit to losing a fair amount of territory. You are very strong outside -- much stronger than the normal joseki -- yet you chose to defend. Next game pick a fight!

makes good defensive shape, but W was not threatening anything. Rather, W was defending against the possibility of B pressing at H15 to expand the B moyo. You let W get away with this in sente.

is another overplay, deep within B influence. You must punish W for such impudence! Your first thought should be something like E10 or F11, rather than C11 which is purely defensive. E10 would go for an outright capture, ending the game, but requires reading. F11 aims to drive W downward, letting B naturally strengthen the two stones there. With pressing moves like E5 available, B should get a good result.

is horribly submissive. You have to look for something better. If you see nothing useful now, then just tenuki and wait for a better opportunity. However, in the actual game, what happens if B blocks at H3, then plays atari underneath at J2 after W cuts? It looks like B gets quite a nice squeeze (giving up the J4 stone).

is a good attack, pushing the weak W group toward the B strength above. But it is difficult to kill a single large group like this. To strengthen the attack, or to get compensation elsewhere, you additional leverage, which you can get here by pressing against the strong W group above.

and

are too soft, as they have no effect on the upper W group. Consider pressing directly at G15. If W hanes, you hane back, then keep pushing to get additional forcing moves, after which K11 becomes very severe, maybe even fatal. (This whole sequence might be even more powerful after first exchanging K11 for J12 or H13, but you would have to read that W could not connect with H14.) If W ignores G15, then H16 is a strong follow-up, likely forcing W to crawl along the second line while B builds center strength. Meanwhile, the W center group remains weak.

looks like you are going for the kill. Good, finally a really strong attack! Both sides made mistakes in the fight, but no matter, this is the attitude you need. Some notes on tactics: Could

block at L13? (Can W do anything outside?) How about

at K15? (Can W save this stone?) If W is going to live anyway, :b101: at J15 leaves the outside B position connected and extremely strong. This much thickness should provide enough territory to win.
:b119: should be at N16 for safety. Killing the two W cutting stones would be enough to win. Live and let die.
NB) In casual English, you can profit (or gain profit) from a profitable attack, which provides either direct profit or indirect benefits. It would sound a little strange to say you can benefit (or gain benefits) from a beneficial attack, but we would all get the idea

. Your English is quite good.