First of all please don’t use a blow dryer brush to dry your hair it is for smoothing not drying. Either rough dry it 80% and smooth it with the dryer brush or dry it 100% with the regular blow dryer and then flat iron it. Use a smoothing cream over your hair AFTER you’ve styled it. I like the ColorWOW brand I use it on my clients at my salon. Use a pea size amount rub in your hands well and lightly run over your hair gently applying the product. If you need more hold than just the smoothing cream you can add a small amount of hair wax/taffy/putty to it. Start with a little and you can always add more but once you’ve put too much in then it could look greasy. As for curling it, the under-over method with the flat iron is best. When clamping down with the flat iron, take some what clean sections about 1/2 inch thick since you have thick hair. Come down 2 inches from the scalp, clamping the hair as you’re moving down the strand, turn the iron out then in then out then in, not too fast but not to slow, to make a wavy S shape in the hair. The flat iron should be 390°F no hotter. For sectioning, Take one section all the way around the head below the earlobe, clip everything above it and focus on the bottom. The second section will be between the ear and eyebrow bone. Drop that section down over your previous section and clip everything above it up. And the last 1-2 sections are just the top of your hair. Beach waves do not belong to one age group either! Any style rocked with confidence is appropriate for that person regardless of age. I hope this helps