Example of a Good Title

Efficacy and safety of intermittent preventive treatment with sulfadoxine-pyrimethamine for malaria in African infants: A pooled analysis of six randomised, placebo-controlled trials

The above title may appear long, but is adequately descriptive of the study it represents, and is highly likely to show up in search results pertaining to this topic. It summarises in a single line, what the study is about.
It contains some keywords that you might search with, in a search engine:
sulfadoxine-pyrimethamine
Malaria
infant
It is split into two parts: the first part describes the study, the second part says what type of study it is. 

If the same title were shortened to: 
Efficacy and safety of treatment with sulfadoxine-pyrimethamine for malaria in African infants

This title is not very specific. It does not tell you what kind of a study it is. If you are looking for randomised controlled trials, you will not know that this is one such study until you read the abstract. 

If the same title were further shortened: 
Treatment for malaria in infants

This title is too broad. Although it has two keywords; malaria and infants, it does not say what type of study it is, and that the findings pertain to African infants, which may not necessarily be applicable to all infants.

The first title on this page is an example of a good title that is descriptive of the study, uses keywords and specifies the type of study. If you are looking for studies on this topic, this title is highly likely to come up in the search results.