public static Map<String, Schema.DescribeFieldResult> getFieldMetaData(
  Schema.DescribeSObjectResult dsor, Set<String> fields) {
	
  // the map to be returned with the final data
  Map<String,Schema.DescribeFieldResult> finalMap = 
    new Map<String, Schema.DescribeFieldResult>();
  // map of all fields in the object
  Map<String, Schema.SObjectField> objectFields = dsor.fields.getMap();
		
  // iterate over the requested fields and get the describe info for each one. 
  // add it to a map with field name as key
  for(String field : fields){
    // skip fields that are not part of the object
    if (objectFields.containsKey(field)) {
      Schema.DescribeFieldResult dr = objectFields.get(field).getDescribe();
      // add the results to the map to be returned
      finalMap.put(field, dr); 
    }
  }
  return finalMap;
}

Set<String> fields = new Set<String>{'name','annualrevenue','BADFIELD'};

Map<String, Schema.DescribeFieldResult> finalMap = 
  Utils.getFieldMetaData(Account.getSObjectType().getDescribe(), fields);

// only print out the 'good' fields
for (String field : new Set<String>{'name','annualrevenue'}) {
  System.debug(finalMap.get(field).getName()); // field name
  System.debug(finalMap.get(field).getType()); // field type
  System.debug(finalMap.get(field).getLength()); // field length
}