To increase the performance in designer
1. Use as much conditions as possible
2. Use array fetch parameter
3. Limit the number of rows in Universe parameters as per 
ur need
4. Resolve loops completely etc.,
To increase performance in reports:
1. Avoid usage of more variables
2. Use indexes on columns 

Still more points are there, i didn't remember. Any body 
can continue this post

To increase the performance in universe:

-as possile as use less number of joins
- avoid use of user objects
- use aggregate awareness

To increase the performance in reports:
- avoid use of user objects

1. Increase array fetch size.
2. Use Bit map indexing on Fact columns.
3. Remove unwanted objects and classes from your universe.
4. Remove unwanted variables, filters and charts from report
5. Always ensure your fact table execute before your 
dimensional table in the FROM clause (Query optimization)
  ex.  Select F1.A
        D1.B
       FROM
        Fact F1,
        Dim D1
6. Use of Derived Tables so that complex calculation can be 
performed at universe level.
7. Aggregate table
8. Remove unwanted alias and context.
9. Always ensure in join condition you have fact table 
appearing at LHS. (F1.A=D1.B)
10. For prompts related columns, have indexing done at DB 
level
11. Also at universe level you can change row count for 
table rows for SQL execution as per requirements.