Evaluate previous undergraduate transcripts to establish what courses have been completed, when they were taken and what grades were earned. Make sure all grades that appear on transcripts are correct. Medical schools have a fairly specific list of prerequisite coursework that must be completed before applying. Biology, inorganic and organic chemistry and physics, for instance, are almost universally required.
Itemize the requirements set forth by all schools to which applications will be submitted. Review their general GPA policies and coursework requirements. Meet with or contact an admissions representative from each school to prioritize coursework that should be pursued to increase a GPA, including courses that might be repeated.
Consider post-baccalaureate programs, which include all the major coursework required by a medical school and often provide smoother transition through the application process or outright acceptance upon completion. Various schools offer them in conjunction with their medical program or independently for students wishing to refresh their coursework and establish the higher GPA required.
Take courses at a local university or community college to replace tarnished grades or provide an increase in GPA. Pursue courses in which success is likely. This may mean registering for fewer courses at once, but dedicating extra time and effort toward earning high grades.