If you want a balanced score it might take some effort, but to just get an academic average of 22 isn't that bad. All you have to do is get a good score on reading, which does not seem difficult at all. My brother only did one practice reading section before the test where he tried to read the passage and then answer the questions and he got around half of it wrong. On test day he decided to skip the passage initially and just skim for the answers, figuring that even if he only gets through 2/3 of the sections, as long as those 2/3 was right, then he did better than he would have otherwise. When he did that he actually finished with 10 minutes to spare and got a 28 on reading, which pulled up his AA to a 23. When I took the DAT this past saturday I have looked at a total of 10 reading questions, used his strategy and got a 27 on reading. From our experiences it seems like you will get about 3-5 questions where the answers is not explicitly stated in the passage. Math is another section which can drastically boost your average with minimal work. As long as you have a good grasp of algebra, all you have to do is memorize the sine identities.
The particularly hard section is bio as how you do there is pretty much proportional to the effort you put forth studying. There really isn't any shortcuts here. For ogro focus on SN2/Sn1 and E2/E1. Aldol condensation also seems like something they like to include at least one question about. Other than that just memorize what different reagents do. The mechanism is not as important on the DAT as it is in orgo class. The road maps in DAT destroyer is really good for this.
Short version: Do well on reading and it will do wonders for your average. All questions that don't ask for a good title for passage, main idea of passage, or tone of paragraph you can pretty much find answer in passage word for word no inference needed