I love investing in things and making proft out of it eventually how do i know waht items are good for invest?

People who buy antiques for collections or just whatever and save it for a long time eventually gets profit out of it as it increase in value over on. How do people know what too buy too make a good investment and eventually gain a profit later in the future. What do i have too do or reasearch? such as stocks how do I know what stocks are best and will eventually appreciate in value later on? what do i need to look for in companys too see if it is a good investment or not? is there accesible information that is FREE that I can look at too see what is good or not? Thanks.