I used to have this question some time ago.
In order for one to be born in western pure land, following are the
requirements:
1) Take refuge of 3 triple gems
2) Vow to reborn in pureland
3) Keep 5 precepts, filial, ten good conducts, bodhicitta
4) Have certain level of meditation practise
The 1st 2 are rather easy to achieve, but the 3rd and 4th one are
relatively difficult. How does one know if he can reborn in the
pureland.
If one fail to "migrate" to pureland, will his karma resulted from
his diligent practise towards pureland automatically allocate a
"cultivation friendly" place for him.
I don't want to go to heaven, I may use up all my merits there. I
want to go to a place that is suitable to continue cultivation for
example, human realm or tushita
heaven.
The late master yinshun encouraged his disciple to vow to go to
tushita heaven bcoz of the lower entry
barrier and most importantly, it is a heaven that one can listen to
dharma spoken by maitreya bodhisatva, who is also the next to be
buddha.
Western pureland is still better, but we should have contingency
plan, isn't it?