How can i gain weight fast. ?

Cruise: Go on a 2 week cruise. Essentially relax and do very little and eat easily accessible high fat foods frequently.

More calories: I can't think of a good reason why anyone should do this unless you were a prize fighter and had to move up a weight class.Regardless,if you eat a lot of calories and don't burn them off,you will gain weight.

Lift and eat right: what are you trying to gain weight for? I assume you want to gain muscle, not fat? There is a lot out there on this topic; way too much to write here but: eat more lean protein and complex carbs (aim for 0.5-1g protein per lb of body weight) and do weight training 3-4 days per week; focus on the big muscle groups (squat, dead, bench, pull ups, dips)