I find that when I gain weight I get stomache fat.
Its not very big but its larger then the rest of my body.
I am naturally thin so I want to be able to gain weight without gaining any stomache fat.
How can I do this? I am 21 and l’m planning to jog regularly, lift weights and eat a balanced diet.

you just answered your own question, cardio, lift weights (muscle weighs more than fat) and eat right. You need to increase your carbs, but only eat complex carbs. You should also eat alot of fish. Take a multi-vitamin supplement and do not eat junk food. Eat at least 5 times per day, breakfast, snack, lunch, snack, and then dinner before 7pm.