I try to get mine to look roughly the same shape as giant wine glasses.
Remove all the low growing branches to give you a foot or two of stem, this will help air circulate underneath, then pick 4 or 5 of the bigger branches which are spreading outwards and upwards from the centre. Trim these back by about a third, to a upwards pointing bud, if you trim them back to a downwards pointing bud then the tip of the branch may start to grow downwards next spring.
Cut everything else on these bigger branches to about two inches in length.
Try and remove anything which is growing into the centre of the wine glass shape, because this will also reduce air circulation and get in the way when you are trying to pick the fruit off the main branches later in the year.
If you like the flavour of this years fruit, then in October you will also have plenty of new growth from which you can take cuttings to start off new plants.