Offer a bonus of up to half the monthly salary for accepting the job offer.
Surprise the candidate with something unexpected that you have not previously mentioned in the offer.
Allocate a budget for the candidate's educational activities in the first year of working for you.
Add a salary increase option after a certain period of time (for example, six months) in the employment contract.
Show the candidates profiles of their future colleagues and make sure these people are directly involved in the interviews.
Ask on what criteria the candidates will decide whether to accept the job at your company or somewhere else. Modify your hiring process to meet all these criteria.