Low Energy

Are you eating enough?
Try tracking your calories for a day or two. You can use a spreadsheet like this to keep track of your calorie, protein, or other nutrient intake. You can check how many calories you need with this calculator.

Are you in the right environment?
Some people feel low energy or are not productive in their bedrooms or houses. Try working in a different space: a coffee shop, a library, the office, an empty classroom, etc.

Are you sleeping enough?
Many people get little and low quality sleep. If possible try adding another hour of sleep to your daily routine. Many of the suggestions in the Difficulty Sleeping article will also increase the quality of your sleep.

Are you anemic?
Anemia can cause low energy, fatigue, and brain fog. Try eating more meat, leafy green vegetables, and other iron-rich foods, or take iron supplements. (Anemia can be an early sign of serious medical conditions; follow up with a doctor if possible.)

Try caffeine or modafinil
See Gwern's writeup on modafinil here.