A lot of times people don’t have the money or time to straighten their hair with a straightener or a flat=iron. I have a very easy way to do it without using anything but a flat paddle brush and a blow dryer.
Start by washing your hair with shampoo and conditioner like normal. For best results, make sure to use conditioner and shampoo for straight hair.
Towel dry your hair until it's damp, not dripping wet.
Brush your hair out on the top with the paddle brush, then flip your hair over and brush it on the bottom (back to front).
Turn the blow dryer on to high and pick up pieces of your hair with the paddle brush, drying from root to end. Continue until most of your hair is dry on the bottom.
Turn off your blow dryer and flip your hair over. Brush it out straight from root to tip.
Turn the blow dryer back on to high and repeat with the paddle brush, grabbing it both directions.