Minecraft fun :D

So ive had minecraft since July 2010 but I dont really find it fun because i dont know what to do on it (like what to build or what challanges to set) but i enjoy it and i enjoy watching people play minecraft such as generikb and thesyndicateproject they always push themselves to build amazing stuff but as soon as i start building something i get bored :( so i dont know what to do because i'll still continue playing. Also i like the texture that generikb uses (Jolicraft) and Syndicates (Dokucraft) but whenever i use them it doesnt seem as intresting :(