In my experience, there are two types of people. There are those who have tried everything exhaustedly and need help getting back on track. Then there are those who have tried very little because they simply don't know what to try.
I recommend people go back to basics and highly recommend one complete regime that's simple to use. It will usually include a cleanser to help remove bacteria which may lead to the appearance of blemishes, a product that'll mattify the skin if it's oily, such as a toner, followed by a moisturer which can help to reduce the appearance of blemishes whilst helping to protect the skin from drying. It's also important to look after your skin regularly.
Some people might try one product for a while and feel it's not working, however I would encourage you to stick with it. However, if a regime is aggravating your skin, I would suggest you stop using it immediately.
You need to tailor-make everything. In my opinion, there is no such thing as 'one size fits all' when it comes to skin. It's not just about layering product after product – you need to understand your skin in order to find the regime to achieve clearer-looking skin. For example, if you have sensitive skin then I would recommend selecting products which are effective for oily, blemish-prone skin but are not heavily perfumed or contain agents that might irritate the skin.