My first travel abroad was to a 1st world country in EU, kung 3rd world country lang naman pupuntahan mo, hindi sila masyado mahigpit, 1st world countries though, it's a different story, dun ka hahanapan ng sangkatutak na documents, I was barred for around 10Mins sa border guard ng Paris dahil wala akong ready na documentation (this was 2nd time around) kasi hindi naman ako hinanapan nung una! but usually, cash and return tickets will do, pinakita ko lang yung around $8K USD na dala ko hehe, binilang na lang nila and poof, ok na.
Sakto yung tips ng ibang espiya, dress just right, pero usually naman hindi mapangmata mga immigration officials, sa Asia lang yun since madaming nagTTNT dito.