no power / wont start

[jcass29]

i went out today and my truck wouldnt start , i have no power other than head lights , no insturments gauges , no dash lights , no power to the dump bed , checked the battery connections and evrything is good , check the starter wires they are good and tight. i am going to buy a service manual today but i could use some help if anyone has any ideas that might point me in the right direction.
thanks