With all due respect to my colleagues here that prefer syndets, I didn't learn to make my own bath and body products to dump more chemicals into my system! I'm a big fan of homemade all natural shampoo bars and I'm thankful that SMF wasn't my first soapmaking forum or I never would have had the pleasure of making homemade shampoo bars.
That being said, the difference between shampoo bars and regular bars is the time it takes to find the choice of oils/fats/butters you find that work for you and for your hair. There's no "one size fits all". For some, that may be coconut-oil-based (copious lather, highly cleansing); for others, that may be olive-oil-based (negligible lather, gentle cleansing), or any variation you can imagine.
Example: I once had a request to make a 100% almond oil (liquid) shampoo for a customer and I was totally blown away by the result. Wonderful, gentle cleansing shampoo that left my hair and scalp totally clean, conditioned, manageable and shiny.
Personally, I've been shampooing for years with every "regular bar" that happens to be in the shower that day, which led to some interesting discoveries. But that first year was challenging. It took time to find the right formula for me. Other CP-ers have the same experience. It's not unusual for a soaper to go back to commercial shampoo for a week or two during that first year before carrying on, as I did. It does take time for your hair to get used to using a non-syndet all natural hard bar.
It's important to rinse thoroughly with increasingly cool water until it's as cold as you can stand it, to close the hair shaft and remove all the soap scum. An acid rinse with apple cider vinegar or lemon (and others) helps remove any residual scum and restores the pH balance to the scalp. A beer rinse adds volume.
For shine, I like to rub a dot or two of argan oil between my palms, then apply to the ends before working it through the rest of my hair.
