for each foot above your "tap" you'll get about 0.43 psi pressure - less hose friction losses.
so a nominal 48" tall tank, on 36" stilts, gives you 7*0.43 = 3 psi when the tank is full, declining to 3*.043 = 1.29 psi as the barrel reaches empty.
I'm sure you've heard the old saying "water seeks its own level" - the impact of that: assuming there is no elevation difference between the pond and you outlet tap, and for convenience you nail the outlet tap to a stake 3 feet off the ground, you'll only see the pressure from the 4 foot (or less) of water in the tank.
the 'normal' water pressure in a home system is 60-80 psi - so the theory of getting "max water presure" is quite dicey. you won't be able to put a spray nozzle on the hose and go at it - but the 3-2 psi range will fill a watering can, for example - somewhat slowly compared to a "house tap"
if the pond is "uphill" from a convenient watering can fill spot, the pressure will be higher.
conversely, if the pond is lower, the pressure at your outlet will be lower.
the other factor to keep in mind, water flowing thru a pipe/hose encounters frictional losses - the longer the hose/pipe, the more pressure you will lose. a bigger diameter hose/pipe will minimize those losses.
without a bit more detail of how high/low the pond is above/below the garden spot, and how far away the pond is, it's not possible to provide any more "design detail"
a "gotcha" to keep in mind with a tank on stilts - make sure there is a fine mesh screen / other barrier to keep debris out of the tank. falling leaves (for example) will eventually clog either the outlet port of the tank or get 'stuck' in the hose/pipe - and there's not much pressure to 'blast them out'