So you’re hitting the gym with one very specific goal: to pack on muscle. You probably already know to focus your time on lifting weights over cardio and to eat plenty of protein—but there’s more to optimizing your gains than those two rules of thumb.

From the must-do basics to lesser-known tips and tricks, here’s what fitness pros recommend focusing on in order to build mass as quickly and effectively as possible.

1. Emphasize The Eccentrics

Tempting as it is to practically let your weights fall to the ground after a grueling set of reps, letting gravity do all of the work for you can short-change your results. “Optimizing your workouts can make a big difference in helping you get muscle gains, and using a slower tempo with your eccentric lifting phase can get you results much faster,” says strength coach Josh Schlottman, C.S.C.S. (FYI: The eccentric or “negative” phase of an exercise is when your muscle actively lengthens under stress, as in when you lower a weight you just lifted.)

“The tempo you use when weightlifting will have a big impact on how fast and big you’re able to get your muscles to grow,” Schlottman continues. Slowing your lower, in particular, makes a major difference. “As you slow down the eccentric phase of an exercise, you create a greater force on your muscle, which maximizes the damage done to muscle fibers and causes your muscles to ultimately grow larger and stronger.” Research backs this up, showing that training with a slow movement speed leads to greater hypertrophy (or gains in muscle mass) than using a faster pace.

So, on your next set of bicep curls, lower the weight down for at least four seconds. Just note that extending that lower for more than six seconds doesn’t seem to be as impactful, Schlottman notes.

2. Don’t Underestimate Hydration

“When doing strength training, you lose a lot of water through sweating. Lack of water impairs muscle recovery and could lead to injury which will prevent the gains you are looking for,” says competitive powerlifter and fitness expert and CEO of Lift Vault Kyle Risley. (In fact, research has linked dehydration with delayed-onset muscle soreness.)

Read More: 8 Fun Ways To Drink More Water When You Hate Water

“If you want to build muscle, you’re probably going to need a lot of protein, which can be hard for the kidneys to process,” adds nutritionist and fitness instructor for Fitness Authority Carly James, Ph.D., M.Sc. “Be kind to them and drink plenty of water to help them flush out those waste products.” A baseline guideline to start with: Divide your body weight (in pounds) in half and down that many ounces of water. (That’s 80 ounces for a 160-pound person, FYI.)

3. Sleep, Sleep, Sleep

Putting in the work at the gym is a must, but if you’re hoping to get big and strong, you’ve also got to get plenty of rest. “Muscle growth occurs when you are resting or asleep—when your pituitary gland releases growth hormone, which helps your muscles repair themselves and grow—so failing to get adequate rest slows down your growth and can lead to illness or injury,” says Risley. 

Though sleep needs vary by person (typically somewhere between seven and nine hours), one easy way to determine your baseline needs is to go to bed at the same time each night and wake up naturally, sans alarm clock, he says. For more on conducting that little experiment, check out our guide to figuring out your own optimal sleep schedule.

4. Get Enough Iron 

We’re talking about the nutrient here, folks, not the iron you pump. In addition to ample protein, you’ve got to get enough iron. “Everybody knows about the importance of protein,” James says. “If you really want to bulk up, though, you need to think about your iron intake, too.” 

It’s not so much that iron builds muscle but that a lack of iron prevents you from doing so. Iron produces a type of protein called myoglobin that carries oxygen to your muscles, explains James. Without ample ability to transport oxygen throughout your body—including those hard-working muscles—you seriously limit your ability to perform and make gains.

The Recommended Dietary Allowances (RDAs) for iron are eight milligrams for men and 18 for women (and even more for pregnant women). “Your iron needs also increase with your activity levels,” James adds. “Therefore, very active people are likely to need more.” (This is especially true for vegan and vegetarian muscle-builders.)

Dark leafy greens, seafood, beans, dried fruit, and red meat are all rich sources of iron. If you think you’re not getting enough iron, consult with a healthcare professional to determine if iron supplementation is right for you.  

5. Do Heavy Compound Exercises

“Focus on big muscles and movements,” says trainer Rohan Arora, C.P.T., founder of Gaining Tactics. “If you are looking to get big and build muscle fast, you cannot do it with isolation exercises alone. Lifting heavy weights and doing compound movements is what will force your entire body to grow.” 

Arora recommends focusing your efforts on big lifts like squats, deadlifts, and bench presses, which target multiple muscle groups simultaneously. Another important strategy? Always start your workout with these compound movements, since they require more energy. “If you leave them for the end, you might not have enough energy to go heavy,” Arora adds.

Read More: 6 Common Strength Training Mistakes That Are Messing With Your Gains

Pushing your muscles to the max on these moves is also really important. If you can churn out 10 reps and have enough in the tank for one or two more after that, you’ll need to increase your resistance in order to trigger optimal muscle growth, explains coach Justin Meissner, C.P.T.

6. Don’t Get Stuck In A Routine Rut

No change, no gains. “Following the same workout and nutrition plan over and over impacts your muscle-building and you will likely hit a roadblock and see plateaus,” Arora says. “In order to continuously build muscle and get bigger, you need to change things up, especially in your training.

“A rule of thumb is to follow a workout routine for eight to 12 weeks, then change it to avoid hitting plateaus,” he says. You can mix things up pretty easily by adding more weight to your exercises, increasing the number of sets and reps you do, increasing the intensity of the workout (by, say, cutting down on rest), and incorporating new exercises altogether.

7. Maintain a calorie surplus

For noticeable muscle gains, you’re going to have to eat more. “Extra calories combined with training leads to muscle growth,” says Arora.

“For optimal muscle gains, consuming anywhere between 10 and 20 percent more calories should be sufficient,” he says. (If you typically eat 2,000 calories per day, that means adding between 200 and 400 calories to your daily diet.) However, if you are looking to get big in a short period of time and do not care about gaining fat, you could go for up to 30 to 40 percent additional calories per day. Check out these smart meal prep tips to prepare ample nutritious food to keep the mass growing.