If you push the caliper pistons right back into the caliper , before you bleed it helps to dispel any air in the caliper . The pistons which push the brake pads can be a tad stiff . I wouldn't advise levering them back using a large flat screwdriver between the disc and pad tho , as that would be terribly bad form
instead I would remove the caliper , loosen the bleed nipple a tad after first fitting a piece of clear hose and then push the pads back against the pistons . Loosening the nipple will make this much easier , then tighten the nipple , refit the caliper and bleed as normal. Alternatively , squire a vacuum bleed pump . These are cheap as chips on the interweb . Connect the pump to the nipple , loosen the nipple and pump away , after first having removed the reservoir cap of course ! This method is quicker , cleaner and will give you rock hard lever feel . There is nothing quite like a rock hard lever !