Tweak SOLR results from right within Admin.
Admin tools include: setting weights to product attributes, creating synonyms, setting stop words, building URL redirects for particular terms.
Leverage product attributes in your catalog to help visitors get the results they are looking for. By assigning higher or lower weights to various attributes (e.g. brand, model, product type), you can manipulate which products appear higher in the list for a given set of terms.
There is an additional option – “Combine sort attribute and direction” – this depends on frontend templates (may not be compatible with your template).
When “Combine sort attribute and direction” is enabled (set to “Yes”), a number of options appear to give you control over the product sorting on the front end.
Stop words are words that do not bear contextual meaning for search, but may frequently be used in sentences. Those words are excluded from full text searching.
Synonyms are another way to give more precise control, though in most SOLR instances stemming is enabled, so there is no need to specify very close synonyms.