I’ve only skimmed through the first two paragraphs but I think it looks good other than maybe an overuse of the topic particle. You really don’t need to have it there every other sentence but that’s a stylistic thing since it’s still grammatically correct.
You may also want to use には or のは instead in a few places if you’ve covered that usage already.
Some of the changes I’ll be suggesting are sort of optional i.e. what you’ve written isn’t wrong, but I think what I’m suggesting might be more natural. Since you haven’t used any brackets, I’ll make what’s ‘optional’ clear by putting it in brackets. By the way, I might end up saying the same things as what some other people have already said above, so if you’ve already fixed something, just ignore what I say about it.
人気のある and 人気がある are both correct, and the choice of particle is just a matter of personal preference and style. If you’re not clear on when you can use の instead of が (the answer is ‘inside a relative clause that modifies/describes a noun’), then just stick to が. You’ll probably learn more about it later.
Separately, I’m not sure why, but I’m not as concerned about the lack of a に in the last sentence. Maybe I feel like it’s more important when discussing something that physically exists in a location. However, I think that in both cases, it technically should be there: 〜にある and 〜にいる are the standard structures.
The reason it’s ‘東京・銀座’ (the reverse of what we usually do in English: ‘in Ginza, Tokyo, Japan’) is because that’s just the normal order of things in Japanese: you start from the biggest overarching location (a country, for instance) and then work your way down. You can see an example in this video on Japanese addresses from Dogen:
It’s 県 (prefecture) and then 区 (district), for instance.
そしと is supposed to be そして, as mentioned by someone else above. I think you might have mixed up そして and と, which is the most common way of saying ‘and’. As for why I suggest cancelling out 天ぷら 近藤は, it’s because the topic is the same as in the previous sentence, so there’s no need to reindicate it. Japanese isn’t like English, in which the subject of every single sentence must be stated. It takes some getting used to, but it makes Japanese more convenient to use than English when it comes to long discussions of the same issue/idea. There’s no need to replace 「です」 with 「で、」if you don’t want to: you can keep the two sentences separate, and there still won’t be no need to use 天ぷら 近藤は a second time. That’s what @alo meant by ‘overuse of topic particle’, which is quite normal for native speakers of European languages learning Japanese.
The next few errors I corrected are just ‘spelling’ mistakes: I think that フライドフード and ヘルシー are supposed to be in katakana all the time, even if they might appear in hiragana in informal contexts. As for the adjectives… おいしい means ‘delicious’ and usually refers to taste in and of itself. No need for 味. You only add a noun when you need to specify what is delicious, including in special cases like 空気がおいしい, which actually means that the air is fresh and clear, and hence ‘delicious’ (i.e. wonderful and pleasing to the senses). The use of the て-form of おいしい (おいしくて) is necessary because Japanese doesn’t join adjectives and verbs using a particle/phrase that means ‘and’; it does so with て-forms (or something called 連用形, which are the masu-stems in the case of verbs) instead. That bit of the sentence means ‘is delicious, and various types of (literally ‘varied’) vegetables…’.
Just a final note on ケーキ と ペストリー と コーヒー in the last sentence: this is not wrong, but technically speaking, if you use と, you’re suggesting you’ve listed everything that they sell. If they sell other types of products, then you should use やs to replace those とs, because you’re raising examples of what they sell, and not listing everything.
がたくさんある is the correct structure, which you used in your first paragraph. Stick to that, and you’ll be fine. As for why it’s usually 銀座三越 and not 三越銀座… I think it’s the same thing as 東京銀座. Here’s the litmus test: try adding の between the elements. Does it fit? Yes? Like with 銀座の三越 (the Mitsukoshi of Ginza)? Then you’re fine. No? Then maybe the order should be reversed. Of course, our best bet is always to check official company websites in such cases, but I think that’s probably the general rule.
I feel that I have to break down the next sentence: at Mitsukoshi Ginza/if we’re talking about Mitsukoshi Ginza (は), we have some people selling dresses and accessories and bags (や because I’m completely certain they sell more than that – I’ve been to Mitsukoshi Ginza – so these are just examples, not the full list; and the whole thing is marked by を because they’re the things being sold) at (で) a popular shopping centre. Alternatively (and this is probably more accurate, since Mitsukoshi Ginza is just one shopping centre if I’m not wrong, even if it’s a really famous one), the sentence I wrote could be interpreted as ‘Mitsukoshi Ginza is (で – て-form of だ) a popular shopping centre, and sells (売っています) dresses, accessories and bags (among other things).’ Your original sentence meant something like ‘About Mitsukoshi Ginza, popularity sells shopping centres, and dresses, accessories and bags are selling [shopping centres] too.’ (Honestly, that interpretation required some extrapolation because there are two がs to which we can’t assign two different roles, but you get the idea.)
For the last sentence in this section, I suggest you add たとえば=‘for example’, and that you split the sentence into two around あります if you want to use でも, because でも is always used at the beginning of a sentence when it means ‘but’ or ‘however’.
にいきました because you’ve actually been there, if I’m understanding correctly. へいきました wouldn’t be wrong either, but it would just indicate that you’ve headed in that direction before, without indicating whether or not you actually arrived. You can’t use を here because Ginza was not a road that you took on the way to somewhere.
I have no clue how to use ビジー correctly in Japanese, but I think it’s calqued on the English ‘busy’, meaning that it should function a lot like an adjective. That’s why I suggest using it with です. I think an alternative to that is にぎやか. It’s な-adjective that means ‘busy’, ‘bustling’, ‘lively’ and so on. As for the rest of that sentence, a mid-sentence ‘but’ can almost always be translated using が or a form of けれども (in order of politeness, we have けれども、けれど and けど). It can never be translated using でも unless you end the sentence and start the next one with でも.
Could I ask what ‘ですそしと’ was supposed to mean? If you intended to say ‘and’, I think 買って alone would suffice, but I don’t want to accidentally delete part of what you wanted to express. That aside, generally speaking, sentences don’t end with て-forms. They can, especially in informal conversation, but in writing, it’s extremely rare, and even when it happens, it’s always implied that the て-form is linked to some other idea that was either expressed previously, or has yet to be expressed. That’s why I decided to link those sentences up. I’m not sure if it would be better to split the sentences about what you did and how you felt about the 天ぷら, because I’m concerned that that sentence will imply that buying stationery and dresses was tasty too. I would split them like this: 「…を食べました。天ぷらはとてもおいしかったです。」However, such a split may not be necessary since it can be inferred that you were talking about the food. Finally, I changed 一番 into とても (=‘very’) because 一番 means ‘the most’ or ‘the best’ or ‘the first’. I personally find it strange without a context for comparison. If you want to say that it was the best you’d had in your entire life, I think you could say
Overall, it was a very nice description of Ginza with lots of relevant ideas and little tidbits. Good job. I hope I didn’t come across too harsh in my corrections, and I’m sorry about the length of my post.