In order to write in active voice, you must find a way to get rid of the helping verbs (or linking verbs like is, are, was, and were). You should use all action verbs. For example:
I painted the house last summer. I washed the exterior using ..... Then I sealed all of the holes.... After the putty dried, I painted the exterior. I used latex paint since it dries quickly and cleans up easily with water. The job took an entire week to complete.....
And so on.