If you're narrating a story or an event that happened in the past, always use the past tense. There are only two exceptions where you can use the present tense even if you are referring to something in the past: (1) Newspaper headlines, (2) the Holy Bible.
Most Filipinos are confused when to use the past tense instead of the present tense. Filipinos are not used to it for the reason that in the Tagalog language, the verb "ay" is used both in the present and past tenses.Another reason is in the thought that if a state of being in the past continues to be in the same state at present, Filipinos use the present tense.
To illustrate, observe the following sentences. "I met my friend a year ago. He has two kids." A Filipino would use the present tense because in his mind his friend still has two kids up to the present day. Remember though, that you are narrating a story here that happened in the past. Therefore, the sentences should have been "I met my friend a year ago. He had two kids." Whether or not your friend remains to have two kids up to this time, use verb in past tense.
In conversational English, the following are acceptable: "I met my friend a while ago. He has two kids." "I met my friend yesterday. He has two kids now." But, "I met my friend a while ago. He told me that he had two kids."
When writing an article, take time to review what you wrote. Examine your sentences and your verbs. Is the thought about the present or the past? Was it 'is' or is it 'was'?