I've never been good in science but usually I could manage a 65, however in Chemistry I can't even reach a 65 to pass the class. My issue in class is tests and exams being 50% of my grade, but no matter how much I study I can't remember anything. So do you guys have any studying tips?

Maybe ask people from your class why the atoms react like that when something happens, learn how chemistry works. If you do, learning it should be easier.

Simplify EVERYTHING. I mean shorten, cut down useless text, bullet point paragraphs. Try using a page for each topic in chemistry and making small notes all over the page. It helps me and I hope it may help you :)
>>2 This could be a good idea too~

One thing that seems to be plaguing you is worry.
While you didn't say it, the majority of people forgetting stuff comes from their nervousness during the test.
Don't worry :P! If anything, now's your chance to go all underdog on this and pull through!
If that way of thinking doesn't work, just don't think about whether or not it's important. A test is a test, whether it's 2% of your grade or 50%. It's all the same.
For me, i just go, "Oh.. I'm taking a test.. ALright then let's do this."
I get great grades.

I had Chemistry. It's incredibly annoying and studying for it can be incredibly difficult, especially if you are like me and aren't inclined towards the subject. That being said, the best way for me to keep stuff like that in my head is to just practice it, you know? Chemistry, as a conceptually heavy science class with mathematics thrown in as well, will challenge you to problem solve and sometimes not all of the variations are represented in class or in homework. Many times I come to a test and find questions I have no idea how to answer, or I do things wrong because I mess up a constant, etc. A good thing to do might be to look up practice online and drill things into your head, and perhaps reading up on the material and then talking about it with somebody would also be good, because sometimes "teaching" people in and of itself is a handy learning device.

I hope you can pull it up, you know, it sucks when you feel like you can't do anything to fix things but I assure you it's definitely possible, just keep trying.

When ever you take notes in a class always review those notes. By review I mean study those notes for about 30-45 mins the night those notes were taken, study those notes for about 30-45 mins the night after those notes were taken and study those notes for about 30-45 mins two night after those notes were taken. This is how my teachers and professors want me to study the content they teach. This is how I study and it really works.

I have lots of tips for this problem.

*Try eating a gum while studying. And when it's you exams time, eat the same gum.
If gum is prohibited why you're taking a test,try some menthol or any mint perfume for your mouth. Everything that could make you taste the same food at your exams and study time.
*When study schedules, don't push yourself too much staying awake at midnight. THAT'S A VERY VERY NO NO. Many students think that's nice, but just NO. Try to sleep early, like 8 or 9. But before sleeping, you should study even few HARD lessons(Of course). Study hard lessons first.
And when you've done studying those hard lessons, DRINK A GLASS OF HEALTHY MILK. Milk helps you to nourish and refresh your mind.
Then in the morning, you should wake up in 4 or 5 to study again.
ALL of it, study. You should make this in a week before your exams.
Hardwork must be there.
*If you're asking about studying in a weekend(Day Time). Well, that's when you can study all the time. But just remember the night study schedule- the tip #2.
*Try to avoid some things that might make your head mixed up. Like thinking about which you'll choose, Anime or Studies. Of course make studies a priority. It's just on a week though. So don't think like your lose Anime and any other new release Anime Ep.
You can also make your favorites a prize, example, If you achieved to memorize your physics lessons or part of it, you'll treat yourself to your favorite expensive food, or Per lesson memorized, 3 episodes of your favorite completed anime series or something that will make you happy.
*When studying, relax. You don't half to harsh yourself saying "I Should Memorize this ASAP". Just trust yourself. Relax and Take everything step by step. Patience is for the good.
*Never forget to pray. But if you're an atheist, just ignore this tip.
*And also for the last one, Trust yourself. Feel relax and confident. It's so good seeing your classmates nervous while your proof is starting to distribute your exam papers, while you, you're excited and very ready and curious about the questions.

So that's all I can say.
This really works on me, I hope it'll work on you too.

1 - Write down / copy out what you want to learn if you learn through doing
2 - Say your facts out loud if you learn better through hearing it

Adding onto what >>7 said– you can also use a scent. Like cologne, perfume, or lotion. They say that smells are the most memory-provoking of your 5 senses.

Using a red pen or highlighting using yellow will help you remember what you write.

When reading textbooks, people usually read straight from start to finish right? But for some people (like me), it's easier to read the introduction, the conclusion, and any charts/diagrams; and then go back and read the entire thing. Some people's brains just like to have the broad concept, and then fill in details afterwards. You can try that and see if it helps you.

To memorize, I mostly either type/write whatever it is repeatedly, saying it out loud as I go, until I get it.

And make sure you take breaks after every hour of studying. But 5-10 minutes only!

If you don't understand any material– I recommend Ms. Kendall on Brightstorm. You can look her up on youtube. As a second choice, you can try khanacademy.org

I'm taking chem too– it's a killer. Good luck, buddy. I hope this helps.

We need an official education section / board / tab

There's a really good book out there I've read a couple of years ago about learning techniques, some of them I even use today. I'm sure there's a ton of similar books out there, but this is the one I know worked for me, maybe stuff that's in here will also work for you:
http://www.amazon.com/Accelerated-Learning-Techniques-Brian-Tracy/dp/0671536842

(You don't need to specifically buy it if you're sly enough to find the book online of course ;)