How can I speed up this SQL view?

How can I speed up this SQL view?

I'm a beginner at this so hope you can help. I'm working in SQL server
2008R2 and have a view that is comprised from four tables all joined
together:
SELECT DISTINCT ad.award_id,
bl.funding_id,
bl.budget_line,
dd4.monthnumberofyear AS month,
dd4.yearcalendar AS year,
CASE
WHEN frb.full_value IS NULL THEN '0'
ELSE frb.full_value
END AS Expenditure_value,
bl.budget_id,
frb.accode,
'Actual' AS Type
FROM dw.dbo.dimdate5 AS dd4
LEFT OUTER JOIN dbo.award_data AS ad
ON dd4.fulldate BETWEEN ad.usethisstartdate AND
ad.usethisenddate
LEFT OUTER JOIN dbo.budget_line AS bl
ON bl.award_id = ad.award_id
LEFT OUTER JOIN dw.dbo.fctresearchbalances AS frb
ON frb.el3 = bl.award_id
AND frb.element4groupidnew = bl.budget_line
AND dd4.yearfiscal = frb.yr
AND dd4.monthnumberfiscal = frb.period
The view has 9 columns and 1.5 million rows and growing. A select * from
this view was taking 20 minutes for all the rows. I added indexes on the
fields in the tables that are joined on and that improved it to 10
minutes. My question is what else could I do to get the select to run
faster?
Many thanks, Violet.