1) ANYWAYS / ANYWAY
“Anyways” at the beginning of a sentence usually indicates that the speaker has resumed a narrative thread: “Anyways, I told Matilda that guy was a lazy bum before she ever married him.” It also occurs at the end of phrases and sentences, meaning “in any case“: “He wasn’t all that good-looking anyways.” A slightly less rustic quality can be imparted to these sentences by substituting the more formal anyway. Neither expression is a good idea in formal written English. The two-word phrase “any way” has many legitimate uses, however: “Is there any way to prevent the impending disaster?”
2) APART/A PART
Paradoxically, the one-word form implies separation while the two-word form implies union. Feuding roommates decide to live apart. Their time together may be a part of their life they will remember with some bitterness.
3) AS FAR AS / AS FAR AS *** IS CONCERNED
Originally people used to say things like “As far as music is concerned, I especially love Baroque opera.” Recently they have begun to drop the “is concerned” part of the phrase. Perhaps this shift was influenced by confusion with a similar phrase, “as for.” “As for money, I don’t have any,” is fine; “As far as money, I don’t have any,” is clumsy.
4) AS FOLLOW / AS FOLLOWS
“My birthday requests are as follows.” This standard phrase doesn’t change number when the items to follow grow from one to many. It’s never correct to say “as follow.”
5) AS PER / IN ACCORDANCE WITH
“Enclosed is the shipment of #2 toggle bolts as per your order of June 14” writes the businessman, unaware that not only is the “as” redundant, he is sounding very old-fashioned and pretentious. The meaning is “in accordance with,” or “in response to the request made”; but it is better to avoid these cumbersome substitutes altogether: “Enclosed is the shipment of bolts you ordered June 14.”