Computer assisted teaching (CAL) is considered to be a modern teaching method, but it is not widely used by teachers because lack of technology and adequate educational softwares in schools; or lack of teachers' knowledge on methodology and computer use. In order to select the most efficient educational software for their class, teachers should know, which are the most important features of educational softwares. It is also important that teachers can develop simple electronic lessons for their classroom, as not every school subject is well covered by educational softwares or the existing softs are not appropriate for every classroom. This paper presents a qualitative research on what in-service teachers consider important when choosing educational software; and how they use these features in electronic lessons developed by them. Teachers' answers about important features of a good educational software, and the electronic lessons made by them were analysed. The results show that even if most of the teachers know how a good educational software should be, many of them can't integrate these features in their electronic lessons because lack of computer knowledge or inadequate time allocated for developing this lesson. The results highlight the importance of organizing practical training courses for CAL.