Our daughter was so impressed with the Wonder Woman movie. I loved what an amazing inspirational character she is for women and especially impressionable young girls.
This is a pattern for an experienced sewer.

Supplies

3 yards lightweight grey fabric
Thread
Sewing machine
Needles
Scissors
Measuring tape
Pen and paper
Large paper for pattern making
Ruler
12 buttons
Belt
Hat
Glasses
Sword
Shield
Black Granny boots
Fusible interfacing
White button down shirt

Step 1: Make a Pattern

Using the measuring tape, take the following measurements:
FOR JACKET:
Neck to shoulder
Chest
Hip
Neck to tailbone
Neck to below knee
Neck
Arm length
Wrist
Shoulder to shoulder

FOR SKIRT
Waist
Waist to ankle

Use the measurements to create the pattern pieces.
Refer to the photos

JACKET
Back: Use the chest, hip, neck, neck to shoulder, neck to tailbone, tailbone to below knee measurements
Front: Use the chest, hip, armhole . The length will be the same as the back measurement from neck to below the knee.
Sleeve: Use the arm , armhole and wrist measurements .
Collar: Use the shoulder to shoulder measurements .
Wrist Strap: Use the wrist measurement.
Pockets: The size is based on the size of the jacket front pattern pieces .

SKIRT
Panels: Use waist , hip and waist to ankle measurements.
Waist: Use waist measurement.

It is always best to baste the pieces together. Then check the fit and adjust as necessary before stitching.

Step 2: Sewing

Refer to the photos.

JACKET
Back: sew from neck to dot. Clip to dot. Press open.
Finish edges of overlap.
Apply interfacing to lining of collar and lining.
Sew linings to jacket fronts .
Turn lining inside and press.
Sew front to back at shoulders and sides.
Sew collars together from dot to dot. Clip corners, turn out and press. Sew collar to Jacket .
Sew arms . Finish wrist edge. Sew wrist straps and sew 2 inches above wrist. . Sew arms to jacket.
Press all seams. Add buttonholes and buttons

SKIRT:
Sew all 4 skirt panels together. Leave open in the front. Finish front edges from waist to bottom.
Sew waist sections together. Sew skirt to waistband. Finish hem .
Add button holes and buttons.