I tried Compeed plasters once and swore never again, because they entered some kind of symbiotic relationship with my blisters and were nearly impossible to get off.
When buying new shoes or boots I put ordinary plasters on all the places where I know I am prone to getting blisters before I go shopping and wear plasters while I am breaking in the new shoes or boots.
If a shoe or boot is not comfortable when I try it on, or is more then very slightly stiff then I don't buy it, because experience has taught me that I cannot break them in.
Try and find the make that suits your feet and never buy another make. This may seem expensive, but one pair of dearer shoes that you know you can use for ever and a day is cheaper in the long run that three or four cheaper pairs that end up in the charity shop.
Always try on new footwear with the stockings or socks you will be using in them.