A situation is a condition or set of circumstances. A particularly unfavorable or unfortunate situation is a plight. While you will sometimes encounter plight used laughingly to describe circumstances that are exceedingly manageable—lacking clean socks, he found himself in a terrible plight—you will more commonly see plight used to discuss truly dire and precarious circumstances, as those faced by workers in perilous conditions, or refugees fleeing home for reasons of personal safety.
To allow is to permit or acknowledge something, the way a teacher might allow a student to be absent, or an insurance company might allow a claim. While not necessarily an enthusiastic show of support, allow implies no effort to hinder something from occurring. Acquiesce, on the other hand, is full of reluctance. To acquiesce is to assent tacitly, or to submit or comply silently or without protest. Typically when a person acquiesces to or in something, they're not thrilled about it, but after objection, debate, or negotiation, they're accepting it with a degree of resignation.
The very common adjective successful is most often used to talk about the attainment of goals or wealth, as a successful career or successful entrepreneur. The synonym fruitful describes things that are or have been highly productive, particularly discussions, collaborations, or intellectual efforts that are constructive or that promise to yield fruit (the metaphorical kind) in abundance. May your writing be fruitful!