There's a good computer tool for learning the states and capitals available at bzcltl.webs.com.
You do not need to know all 50 states and their capitals. You only need to know the following state-related facts
(1) one of the states that border Canada
(2) one of the states that border Mexico
(3) Three of original 13 colonies (states)
(4) Governor of your residence states (google with keyword governor and your state name to locate the website of your governor for examples such as
http://www.governor.state.pa.us/portal/server.pt/community/governor's_web_site/2985 and
http://governor.delaware.gov/
and
http://www.governor.maryland.gov/)
(5) Capital of your residence state
(6) One of two senators of your residence state (find out at
www.senate.gov)
(7) Your house representative (Find out by using your zipcode (5 digit one and 4 digit subcode at
www.house.gov)
For (1),(2),(3) if your residence state happens to be the answer then it is highly recommended you use your own state
for answers to those questions since you never forget your own state.
Verify governors, senators, and your house representative information on the eve of your interview in case of any changes like
resgination, reelection, impeachment, etc
I am not sure if (7) the question "name your house representative" has ever been asked in citizenship interview or not. Some big states
may have dozen house representaives and some USCIS DO may cover several neighborimng states so the USCIS may not have a complete
list of house representative available. And you need to locate yours by using 5 digit zipcide and 4 digit subzipcode but the USCIS IOs may find it troublesome to verify (you may forget yoru 4 digit subzipcode at the interview) so they may be reluctant to use this question. Unlike the senator question for which any senator from your state is a good answer, you can not just name any house represenative from your state. You must name the house representative
in your zipcode&subzipcode area. For those of you who use two addresses, it is recommendable that you locate governor, senators, and house representaives
for both of your address.