You can meaningfully sharpen reasoning skills, working memory, and test performance through training and education, but raising your underlying general intelligence (g) substantially and permanently is not well supported — core g is largely heritable. The honest answer is that some gains are real and some popular claims are overstated.
You can improve your measured performance and some specific skills, but large, permanent jumps in core intelligence are unlikely. Fluid intelligence (Gf) can shift modestly with sustained working-memory and reasoning practice, and more education reliably raises scores by a few points. However, general intelligence (g) is substantially heritable, so the realistic goal is to reach and maintain your potential, not to add 30 points.
Brain-training games mostly make you better at those specific games, with limited transfer to general intelligence. Research shows practice improves the trained task and sometimes closely related skills, but the evidence for broad, lasting IQ gains is weak. Working-memory training can produce small short-term improvements in fluid reasoning, though these effects tend to fade without continued practice.
Good sleep, regular exercise, reading, and learning new skills all help you perform at your cognitive best. Sleep consolidates memory and restores attention, aerobic exercise supports brain health, and continual learning builds knowledge (crystallized intelligence) over a lifetime. These habits won't turn an average score into a gifted one, but they protect and maximize the ability you have.
Fluid intelligence (Gf) is your ability to reason and solve novel problems, while crystallized intelligence (Gc) is accumulated knowledge and skills. Gf tends to peak in early adulthood and is harder to change, whereas Gc keeps growing for decades through reading, education, and experience. Many lifelong learning gains show up in crystallized intelligence, which is why staying mentally active pays off over time.
You can raise an IQ-test score modestly by getting familiar with the question types, sleeping well, and staying calm and focused during the test. Practicing pattern-recognition puzzles like matrices reduces the 'novelty penalty' of unfamiliar formats, which is a real effect. Just remember this improves your test score, not necessarily your underlying intelligence, so treat any single result as an estimate.