If you don't know your way around a weight room, heading to the gym can be intimidating -- and even dangerous . But paying attention to a few simple rules of proper technique can make you slimmer, stronger and healthier all over.

That's why we asked John Romaniello, trainer, author and founder of Roman Fitness Systems to show us what's what when it comes to strength training.

He'll be helping us tackle some of the most common mistakes we all make while building muscle, plus giving us tips and tricks for better form. This week, we're perfecting the plank.

The Faux Pas: Planks are generally a safe and effective ab exercise, but bad form can hurt the shoulders and back . "Like the pushup, the mistake here is that people collapse at the lower back," says Romaniello.

The Fix: "We fix this by placing something like a broomstick on the client's back, coaching them that there should be three even points of contact: the top of the head, between the shoulder blades and between the buttocks," he says.

Have a workout buddy help you align your spine, as Romaniello demonstrates here.

"If they can feel all three points of contact, they are in alignment and the core will be engaged," he says.

Tell us how it goes in the comments below, and be sure to check back over the following weeks to fix your squats, bicep curls and more.

Check out more in our Fix Your Form series below:

Photos by Damon Dahlen, AOL

• Day 2: Fix Your Form: How To Do The Perfect Crunch

• Day 3: HuffPost Workouts: Music As A 'Getaway'

• Day 4: You Tried It: Amy Dixon's Hard Core Definitions

• Day 5: Buddy Up: Celebrity Couples Who Exercise Together

• Day 6: Memorial Day Chores: How Many Calories Do You Burn?

• Day 7: Bringing The Fun Back To Fitness

• Day 8: Can You Get Fit At Your Memorial Day Garden Party?

• Day 9: Fix Your Form: How To Do The Perfect Dumbbell Row

• Day 10: Stacy Berman's 30-Minute Circuit Workout

• Day 11: The Bicep Curl: A Total-Body Workout?

• Day 12: How To Look Good In A T-Shirt

• Day 13: Celebrities' Favorite Outdoor Workouts

• Day 14: Sweat Into Summer With Indoor Cycling

• Day 15: How To Build Muscle Fast!