Prefer “useful” or “helpful”, where possible.
Ascertain
Use “find out”.
Appraise, Apprise
To “appraise” is to form a judgement about the value of something. You can appraise a candidate for a job by interviewing him or her, or a race-horse from his appearance in the paddock. It is sometimes confused with “apprise”, which means inform, and is better replaced by “inform” in any case.
Around
It is still somewhat of an Americanism to use “around” for “about” or “roughly”, as in “around 60°”. Avoid the practice.
Aforementioned, Aforesaid
These are lawyers’ words. In ordinary writing, “the aforesaid notice” can usually become “the notice” or “this notice” or “it”.
Adjust, Adjustment
If you mean “change”, say so.
Adjacent
Use “near” or “next to”.
Accordingly
Prefer “so” or “therefore”.
Dependant
In the ordinary British usage of today “dependant” is a noun meaning “a person who depends on another for support, etc.”. “Dependent” is an adjective meaning relying on or subject to something else. Dependants are dependent on the person whose dependants they are.
Acquire
Use “get” or “buy” or “win” according to which you mean.