This paper presents major challenges and lessons learned during the process of including and adapting modern medical informatics concepts in challenging circumstances of a health care organization in the Republic of Serbia. The processes of choosing the overall software architecture, application development and later software deployment are examined, and the most critical places (slow network, slow workstations, repetitive data entry, wrong data entered, inappropriate and complex GUI, and low IT knowledge of an end-user) are pointed out, and the general solving strategies are defined. The mentioned strategies are joined together as a general approach for maintaining a complete medical information system life-cycle. Eventually, this approach provides shorter training, efficient support during deployment, more comfortable and efficient work, and makes positive impact on adoption process. In a view of this, our main objective is to specify development and deployment guidelines that can be applied for the information systems developed in different developing countries facing similar problems.