Improved catalogsearch for magento forked from Mikkel Ricky's improved catalogsearch
After you install the "improved catalogsearch" module. You can make changes to the weight of each individual attribute from System > Configuration > Catalog > Catalog Search Weight.
Lower values = more relevance. For example, if SKU + Name are 100 and both Descriptions are 200 a search containing a SKU or partial name match should be higher up in the results vs matches with mentions of the sku or name in it's description.
Changes to the weights require a reindex of the catalogsearch index.