Shampoo your hair thoroughly. This will obviously remove product from the hair. If there is grease, oil, and product in your hair it will weigh it down(leaving hair flat) and cause it to frizz.
Personally I like to apply the shampoo to my hair prior to it being wet. This is because my hair type makes product sit on-top my hair instead of being taken in by my hair, it also makes my hair soft.
After thoroughly rinsing out the shampoo (repeat if needed) lather your conditioner and rinse(repeating is not recommended because it may cause hair to be greasy).
Rinse out shampoo with cold water (not freezing). When you use warm water on your hair, it causes the follicles to open creating frizz (kinda like your pores, right?)
Apply a heat protectant of your choice. You may use either a serum or spray. Apply evenly to hair. Whether or not you use protectant will not effect the straightness of your hair it will just protect.
Apply a very small amount of anti-frizz serum, mousse, or spray (whichever you chose will work). Start application from ends and work your way up to your roots(don't use too much or it will be greasy)
Apply a straightening balm to your hair. This is a crucial step as it will make hair stay and become straight. You don't need to apply a lot to your roots.
Comb hair with a comb, a wide tooth comb is best (brushing hair with a brush while hair is wet is damaging and causes split ends).
OPTIONAL: blow dry hair (low setting is the best if you're not in a rush).
Use a brush to dry straight.
This is an additonal step that only needs to be taken if you own a similar product. Apply a heat styling hair spray. This will make your hair stay straight without feeling crusty and sticky.
Brush the spray through your hair with a brush.
Use a straightener and straighten your hair. Section off your hair if it isn't somewhat straight from the previous steps.
Hope this helps to make your hair become and stay straight.
When I woke up it was still straight! ( this photo is NOT from when I woke up).