When your body transitions from active to resting, everything slows down, and temperature drops. Raising the temperature from a hot shower or a workout session will slow that process down, making it more difficult to sleep. If you need exercise to get tired, or a shower to get comfortable, start it earlier so you have at least thirty minutes to cool down before going to sleep. If you want to shower right before bed, it's okay to take a warm shower, as this will not interfere with your sleep. Your brain chemistry interprets blue light as early dawn, which makes your brain more active. Phones, game consoles, and computers are all sources of blue light. Games, work, puzzles, and other activities that involve mental effort may make it especially difficult to sleep. If you decide to use your computer at night, install Flux to make your computer screen change to redder and pinker "sunset" colors at night. You probably know that caffeine and sugar keep you awake, including caffeine found in soda and chocolate. Other substances that disturb your sleep include B-vitamins, steroidal medication for asthma, beta-blockers, opiates, ginseng, and guarana. If you take any of these as regular evening supplements, take them earlier in the day instead.  Do not change your medication schedule without consulting a doctor. Drinking more water can help pass chemicals through your body faster, but this can be counterproductive if you end up waking up in the night to pee. The rush from cigarettes or any tobacco source can keep you up or cause anxious, restless slumber. The alcohol advice may seem more unusual, since alcohol puts you to sleep. The rhythm of your sleep after alcohol, however, is significantly disrupted. Avoid alcohol in the two to three hours before bed, or you might wake up in the night, or wake up tired in the morning. If you are having trouble sticking to a sleep schedule or sleeping the whole night through, melatonin can safely be used to encourage this behavior. For severe insomnia, doctor-prescribed sleep...

TL;DR in Indonesian:
Hati-hati terhadap mandi air panas dan olahraga sebelum tidur. Hindari hampir semua alat elektronik. Hindari vitamin, suplemen, dan makanan yang merangsang. Hindari alkohol dan rokok sebelum tidur. Minum obat tidur bila diperlukan. Bicarakan dengan dokter tentang apnea tidur.