Shoujo Kai is a teen magazine which means ‘A Girls’ Worlds’ that is targeted at a female audience between the ages of 10 to 18 whose interests include fantasy, [Since you have a few good answers, I'm removing most of your essay to protect agains Internet plagiarism. Staff]
If you are actually writing an essay rather than simply writing a report on the magazine, you need a thesis statement. You need a "bright idea" about the magazine that you can prove; or you can make it about something you disprove. In essay writing of all kinds, the objective is to become part of an academic "conversation" where you present a controversial, unusual, new, or otherwise debatable "argument" (meaning topic of discussion; very different from quarrel) that adds a new point of view, enlightenment, insight or interest into the topic at hand. So, in a word, as they say, unless this is simply a report, you must form a debatable idea about the magazine, present your reasons for your idea (these are called your arguments) and make a detailed and convincing case for your perspective.
Additionally, you need to look up the definitions of some words and avoid using a thesaurus until your mastery of English lexical defintions is keen enough to understand the sometimes subtle differences between similar words. Specifically, "suggests" is too conditional a word to apply to careful, painstaking, costly, deliberate marketing decisions to expand a product to an international market. Similarly, no marketing decisions are ever undertaken to "hint" at the market niche of a product: the risk of missing the meaning of a "hint"--a covert and hardly noticeable suggestion--is too great to risk the success of a marketing campaign and an entire product on. I would recommend (much more firm and confident than "suggest") that you actually mean the simple and straightforward words "prove" and "show." [Note the comma after "cultures" separating two full independent clauses. You might also add the hedging word "intended": "the magazine is intendedfor both cultures, ...." Remember that hedging and mitigating is necessary in essays.]
Both Japanese and English translations exist proving that the magazine is for both cultures, and the masthead “Shoujo Kai” shows that the genre of the magazine is anime.
Hedge: the act or a method of reducing the risk of loss of an argument; a cautious or evasive statement (Collins Dictionary): e.g., intended, perhaps, possibly, etc.
Mitigate: to make or become less severe or harsh; moderate (Collins Dictionary): e.g., may, might, could, etc.
First Paragraph: Italicize the name of the magazine. Rephrase first sentence to omit the linking verb 'is'. Use 'targets' instead, like this: "Shoujo Kai, a teen magazine which means ‘A Girls’ Worlds’, targets a female..." Any time possible remove as many linking verbs as you can and replace them with stronger, action verbs, which will strengthen your writing. The second sentence feels awkward and should be reworded. I understand what you are trying to say, but it comes across as a little wordy, so try a little reorganization into a complex sentence, such as "Since the publishers make the magazine available in both English and Japanese translations, both cultures can enjoy..." I would make the last part about the name of the magazine a separate sentence.
Second Paragraph: On the first sentence, try to go back and omit the 'is' verbs; instead of saying 'is looking' just use 'looks'. Your description of the character is direct and detailed. Instead of saying 'this magazine' substitute the actual name of the magazine.
Third paragraph: Your color analysis in this paragraph is well done, and only a few minor structural changes are needed. The first sentence needs either a conjunction or a semi-colon. I recommend that you insert a semi-colon after the word 'pink,' like this example: "pink; these colors evoke emotions..." The sentence is pretty lengthy, so you could also break it into two different sentences. On the second sentence, you should change your word choice on the word 'provokes' to something with a little less antagonistic connotation like 'suggests' or 'reflects'. Change 'that implies' to 'which implies'. You have a pretty heavy hand with 'that'--it is always best to go back and add variety by changing up some of your word choices. I also suggest changing 'harmonizing' to 'harmonious'.