Part one.
(delete, add; read the comment after the sentence)

Здррравствуйте
В четвёртый раз, что я пишу в своём блокноте. Сегодня, я проснулся очень рано и не смог заснуть снова.
Это просто блин когда происходит, и сейчас я чувствую себя вялым. (word "блин" the way you meant to use it (not a pancake) doesn't really mean anything, so you can't do what you did with it. Consider "блин" being equal to "damn" from sentences like "Damn, hate when this happens". While "блин" is relatively neutral, you should avoid using it pretty much in the same situations where you wouldn't use "damn". To correct the existing sentence you can do: "Блин, (ненавижу)/(не люблю) когда такое происходит, потому что теперь я чувствую себя вялым")
(To be precise though, "блин" is a soft version of "бл*ть"(they even sound close, depending on how we spell it, and that (spelling) would actualy define the level of its rudness), which is a pretty much direct equivalent of english "fu*k" in all its possible forms and uses (execept ones directly implying sexual intercourse). Yep, a classic case of cultural exchange here :D
Несмотря на это, я намерен посмотреть другойочередной фильм на русском.
Я смотрел "Брат 2" очень давно и не понял *его достаточно, чтобы *он мог понравиться мне*(мне понравиться). (блин, I can't make it sound good AND brief no matter what I do (while trying to keep the possible original meaning), so you can either use a version with green additions (but it's still considered broken) or: "Я уже смотрел фильм "Брат 2", но это было довольно давно, потому тогда я не смог понять его в достаточной степени, чтобы он мог мне понравиться")
(ой, уже знаю, что я облажался тут) ("я" is not a mistake here, but it sounds more natural without it, since the form of verbs already tells us that it is "я" who does it)

And yes, it happened again. Hate this " italki correction game" when you already make everything as short as possible (while I obviously want to tell more, but that's not what I'm complaining here), then shorten it even more, then even more, when it is 500 characters inside the limit already, and, no matter what you do, it still won't let you post that sh*t. So, made it a bit longer (but still not as long as the original was - some parts are lost forever) and will post it in two parts.

Part two:

Может быть, теперь я смогу понимать еще. ("в/на этот раз"="this time" sounds better, but your version is fine;  The other one needs to be corrected: "я смогу понять больше"/"я больше пойму")
Всё равно, был интересный фильм для меня, ("(Всё равно)/(Тем не менее), фильм (был мне интересен)/(мне понравился),")
потому что я наблюдал стереотипы американскогой культуры. (while trying to correct, you should probably change the meaning of this sentence to "потому что он указал мне на стереотипы американской культуры" or "даёт посмотреть на американскую культуру со стороны" or ...)
Например, на приветствие: "How are you?", я часто отвечаю: "Hi, how are you?".
Никогда не думал много о факте, что никто не ожидает реального ответа. (just use "Никогда не задумывался"; you can still add "о том факте" to it, but it's probably better off without it)
Завтра, я отвечу с настоящим ответом :D. (You can leave it like this: "Завтра (я) отвечу настоящим ответом", and, however, many would say that it needs to be corrected (since it's kind of "масло масленное"="oily oil" about "отвечу ответом"), it actually fits here nicely. But since it's hard to explain when things like that fit and when not, you better avoid those "масло масленное" situations  in the future. So, you can make it "Завтра отвечу по-настоящему")
Музыка в этом фильме просто отличная, я всё еще слушаю её. "Мне стали слишком малы твои тертые джинсыыыыы..." ("до сих пор её слушаю" would sound more natural, but your version is fine).
До встречи!

It's a decent text! Very understandable, next level stuff is in use. Keep up the good work!

P.S. I would recommend adding an english version of your texts, so we could see where some mistakes come from and help you express things the way YOU meant them (not the way WE think you meant them)

First of all, despite all the following corrections, you made yourself understood - keep up the good work.
In the future add an english translation to your texts though, so it would be easier for us to see where your mistakes come from.
If making yourself understood is not enough for you (which is great), then, well, you asked for it:

ВНа этой картинке я справа сижу(it's better to call it a photo. Changing "справа сижу" to "сижу справа" merely makes it sound better, no real mistake here.  *also you are more like in the middle, 'photographycally' speaking)
Я ем некоторые закуски и пью мексиканскийое пиво (on top of "некоторые закуски" sounding broken here, we can see that you are eating 'something', but with this sentence you don't make it any clearer for us what it is you're eating; so I suggest dropping it entirely    or    just leave a part about mexican beer    or    tell us exactly what you are eating)
Слева от меня сидит жена моего кузена. Слева от неё сидит её муж (since there are only 2 people sitting to the left of you and one of them is a female and the other one is a male, it would be enough for you to say something like "my cousin with his wife"="мой кузен со своей женой"="мой кузен с женой")(also it is better to use "двоюродный брат/двоюродная сестра" instead of "кузен/кузина" - that's how russians name this types of relatives and although the word "кузен" does exist in russian, I bet that not that many people would actually know who is meant by it). Он мой кузен (we figured that one out from the previous sentences)
Напротив нас сидят друьзя её сына (they both are female, so using "подруги" instead of "друзья" is preferable, maybe even mandatory if you build your sentence this way. *however if you mean those two girls and the owner of those sticking leg and arm  and/or  those who we can't see but they also were in front of you , than this sentence would be correct). Позади нас сидят мой папа со себойсвоей подругой (или "мой папа и его подруга"?) (both "со своей подругой" and "и его подруга" would be correct)(to be precise though, you should probably say: "Прямо за мной (right behind me) сидит мой отец со своей подругой")

..to be continued in the message below (although I am inside a character limit, it just won't let me post it in one correction message)

(second part of my correction message):
Напротив них сидят две мои тети и один моего дядьёв (я хочу сказать что у меня ещё тети и дядья но они не в картинке) (you can change "и один моего дядьёв" to "и один из моих дядь". such version of "дядя" would sound kind of strange, but people would 100% understand what you've meant; it's not grammatically correct though) (but later you say that you also have more than 2 aunts, so you should've done something 'with them' like you did with 'your uncle' to show that;  however that would brake the sentence entirely, so the best way to sound natural + inform us that you have more uncles/aunts than we can see   is probably what you already did with those brackets:  "Напротив них сидят две мои тёти и дядя (у меня есть еще дяди и тёти, но их нет на фото)"
Слева от подругыи папы ("папиной подруги" sounds better) сидят дедушка с бабущкой (*Is there a "geographical' mistake? If the man right behind you is your father, than this sentences should sound: "Слева от папы сидят дедушка с бабушкой" , if he is not, however, then there are changes to be made in the previous sentences)
Это день был рождение моего дедушкыи  (here is the translation of what's written here now: "is day was birth of my grandpa", so when people suggest to swap "день" and "был" (on top of changing the ending: рождениЯ) it's not because it just sounds better, but because it changes the meaning to "this was the birthday of my grandpa". You can also do it this way: "Этот день был днём рождения моего дедушки"="This day was the birthday of my grandpa", but it doesn't really fit in here, the same way the english translation of it doesn't) (also you should probably start your text by saying that this photo was made on your grandfather's birthday).

I hope that despite my broken english you would be able to understand what I was trying to say ;)