1. You think of something clever. You say:   
'I have had an idea.'
'I had an idea.'

2. Your friend says that you look tired'. You say:   
'I didn't sleep well recently.'
'I haven't been sleeping well.'

3. Your host asks if you are enjoying the party. You say:   
'I have been having a wonderful time.'
'I am having a wonderful time.'

4. You are leaving the party. You tell your host:   
'I have had a wonderful time.'
'I was having a wonderful time.'

5. Someone asks if you know Bill Jones. You say:   
'I have never heard of him.'
'I did not hear of him.'

6. Someone asks where you went for your holiday. You reply:   
'I have been going to France.'
'I went to France.'

7. Someone asks where you are going for your holiday. You say:   
'I have been going to France a lot recently. I'll try Spain this year.'
'I went to France a lot recently. I'll try Spain this year.'

8. Your friend asks how many questions you have done. You say:   
'I have answered seven.'
'I have been answering the eighth.'