この雑誌は英語の使い方に注意した方が良い。

I saw this magazine on the newsstand the other day.

• newsstand 【名】〈米〉ニューススタンド◆駅・路上などで本・新聞を売る露店（小さな売店）

The caption above the five portraits on the cover says:

× NEW HABITS FOR MANAGING YOUR TIME AND IDEA

It should say:

NEW HABITS FOR MANAGING YOUR TIME AND IDEAS

"Idea" is a countable noun. If you don't use the plural in this case, it sounds like you have only one idea. That's certainly not what this magazine means.

However, if you use "idea" as a singular noun, since it is countable, you must use something like "a" or "the" in front of it.

If a restaurant makes a mistake with their English usage, that's one thing.

• That's one thing. あれは許せるけど、... <- not so sure about this translation, but...

A magazine, on the other hand, has a close relationship to language. How could they not ask a native speaker to check their English usage, especially on the cover?

• かと言って (かといって) (exp) (uk) having said that; on the other hand; (definition from Edict)
  
• その反面 (そのはんめん) (n) on the other hand; (definition from Edict)

If I were the editor, I'd be really embarrassed.