Here are three straight forward steps to standardized test taking that are guaranteed to get you to your best possible score in as little as a month. In order to follow this guide, you will need access to at least three official practice tests and answers (or automatic online scoring for some tests). I would recommend an official practice guide with explanations and additional study material because they also usually come with practice tests and answers.
The first thing to do when taking a standardized test is to cover all of the material. A good way to learn about the test, what it covers, and how it's formatted, is to give yourself enough time to go through the entire test (as if it were a real test) without a timer. That way you can carefully give each question attention, and make sure that your score is not impacted by time pressure or nerves. Make sure to give yourself enough time to get through the entire test in one sitting, or else split the test in half and do it over the course of two days. I would estimate taking twice as much time on this practice test as you will on the actual test and next practice tests.
Once you have completed an entire test and gotten it scored, you will have to review material. Ideally, go through every single question over the course of a week or two. Make sure you know what the right answer is and why it's the right answer. If you don't have much time, first go over the questions you had no idea how to answer, and then go over other questions you understood halfway but were then tricked by the test writers' "almost" answers, which are common across all standardized tests. Go over as much of your test as possible and make sure you understand the answer to every single question.
Once you have studied all or most of the material that is covered on the test, the only thing you can do is practice. Take as many timed practice tests (all at once, or broken up by section) as you can. Make sure you use a timer to make the experience as realistic as possible. Try to take full practice tests all at once whenever possible. You should keep taking practice tests (and reviewing your wrong answers) until you get the same score two or three times in a row. This is called a plateau and will represent the best possible score that you can get within the given time constraints.
Once you've hit your plateau, you're ready to take the real test! Of course, make sure that you're well rested and have eaten a full breakfast on the day of the test. And remember not to panic, at this point, you should be able to ace this test in your sleep. Good luck!