I use google keyword tool or the google trends. check the tag after I receive the following: For Google the preposition is nonsense: example: travel to Vietnam, travel in Vietnam, Vietnam and travel, Vietnam travel on Google understands that all 1: Vietnam travel. If we examine the human perspective this is google the missing. I check the number of search by keyword: travel to Vietnam, travel in Vietnam, Vietnam and travel, travel on Vietnam has one result: local monthly search: 110,000 / month. Need share everybody
when using the google keyword tool be sure to check the "phrase match" and [exact match] boxes on the left after you do a search. this will give you a better idea of searches for the keywords you're looking at.