There are several approaches you can use:

Most important:

instead of applying a function to your columns rewrite it as SARGable arguments:

datediff(d, i.LstMdfation, getdate()) < 30

-- would be

i.LstMdfation>dateadd(dd, -30, getdate())

Another option that usually helps is preaggregation.

Find the table that would be reduced the most by your where conditions and populate that table as an indexed temp table and use this table in your query.

Furthermore, you're calling Artcl at least four times. Maybe the query itself can be rewritten to be much more efficient.

And finally, there might be a missing index issue, too. Check the execution plan for best index usage.