Streaks occur when cleaning solution runs down from your sponge, creating a trail over the dirty, lower portion of the wall. To avoid these streaks, the trick is to clean from the bottom up. This way, any excess cleaning solution that drips over the clean wall can be wiped up and is less likely to cause streaks. Another important tip is to dust the wall thoroughly—working from the top down—before cleaning. This reduces the amount of dirt on the wall to help minimize streaking. A mild cleanser is recommended for any type of painted wall.
Dust your walls from top to bottom with a microfiber duster. Starting at the top keeps dry dust and dirt from falling on sections you've already dusted. Wipe along the baseboard or bottom of the wall and the floor (as applicable) with a damp cloth to remove any dust that has fallen there.
Mix 1/2 cup of Borax with a gallon of warm water in a bucket. Fill a second bucket with clean water.
Dip a sponge in the cleaning mixture and begin cleaning the wall at the bottom and working upward. Scrub the wall with circular motions, covering a workable area of only a few feet.
Dampen a clean cloth in the bucket of clean water and wipe the cleaned wall area to rinse the surface. Wipe up any drips with the cloth to prevent streaking. Dry the rinsed area with a clean, dry cloth.
Repeat the cleaning, rinsing and drying process on the wall area just above the cleaned portion, making sure to wipe up any drips. Clean the next area above until you reach the ceiling, then move down the wall and clean from bottom up in the same fashion. Repeat this process until the entire wall is clean.