To make a spell you must first learn the basics. Such as moon faze, meditation, the colors that fall under that spell(money:green love: pink etc.), know exactly what you want the outcome of the spell you want to be, etc. You don't have to have all the tools, but it would help, some spells can be cast without any tools. And as for your "nobody believing me" problem, just don't worry about it.
All you need to make magic spells is knowledge on the topic itself and all that involves it . This also means not having unrealistic or ridiculousness notions on it.
When you say "All of those stuff" , are you perhaps referring to tools , materials and offerings?
For tools , most will tell you it is unnecessary as it is just something for you to channel your focus and aide your work.
For materials and offerings , it is entirely depends on what you are doing. If you are trying to appease an entity or being , an offering is always a viable option , though there are others. it depends on what you are trying to do .
I also don't think there is a need for you to prove to others that magick is true , I frankly do not see why one has the need to try such a thing and to me , it seems that the individual is pursuing the art for the most inappropriate reasons , doing it do to Wow , Inpress or whichever other reasons.