I'm going to try indexing tables in SQL Server for the first time. I need some advice as to the best method.

Firstly I have three tables containing location data (state, city, district):

tbl_lookup_state
ID int(4) Identity NOT NULL
state_desc varchar(50) NOT NULL

tbl_lookup_city
ID int(4) Identity NOT NULL
stateID int(4) NOT NULL
city_desc varchar(50) NOT NULL

tbl_lookup_district
ID int(4) Identity NOT NULL
cityID int(4) NOT NULL
district_desc varchar(50) NOT NULL

Queries on these tables is always by ID. They are then subsequently sorted by the text description field.

Is it best to use clustered indexes on the ID field?

I also have another table that holds far more information and can be queried against multiple fields - does this need an unclustered index?

Advice on this for a newbie would be appreciated.

DJ