Alright this is gonna be a long reply, but very detailed. (Wall-of-text incoming!)
As david and krztina have said, its an individual thing. You don't dictate your basal needs, your body does :) The first step is to find out EXACTLY what those basal needs are. Here's what I did:
First, split the day into three 8 hour segments ( I used midnight-8am, 8am-4pm, 4pm-midnight).
Next, the testing procedures are the same for all three segments: Start each segment so that your last bolus or food was 2 hours prior, 3 is best. This way there is no IOB or food waiting to digest when you begin your test. Try and start the test with a reasonable BG (For me that means between 100-150. Its really not relevant for this test, just be at a reasonable range).
For the next 8 hours, follow your normal schedule. Drinking water is fine, but avoid ANYTHING that would or could alter BG (caffeine, food, etc). Test every hour and track your results. Don't correct your BG at all, unless its health threatening. If you drop to 80, fine. If you rise to 210, fine. Just track the results. At the end of your 8 hour period, eat (you will be hungry haha) and correct any highs.
Do this test 3 times per 8 hour block. So, that will be a total of 24 tests (this took me about 6 weeks to complete). Yes, there will be a few nights where you have to get up every hour.
Once you've got all 24 test blocks done, merge and study the results for each 8 hour block. You should see a trend (i.e. slight rise or drop at about the same time each test period, BIG rise or drop in a certain time period, etc).
With this data, you should be able to determine when basals need to rise or lower, and by how much (you should have already done testing for I:C ratio, and how many BG points 1 unit will drop you). Depending on what insulin you're using, adjust your basal PRIOR to the rise or drop (to accommodate the time it takes for insulin to start working). For example for me, at approx. 4am every morning, my BG rose drastically (dawn phenomenon). I use novolog, so increased my basal starting at 3:15am.
So, after all your tweaks, this will be your rough draft or beta basal. You aren't quite done yet :) After your tweaks, you will repeat the test one more time to confirm your adjustments are accurate. If you have a rise or fall AFTER your tweaks are out into place of more than 20 points, repeat the test AGAIN to confirm the rise and fall again, and adjust, if necessary, as needed.
This is a very long test; however, in most cases, you only need to do it once. Once your pump is set up you can forget about it and feel confident that no matter what time of day it is your insulin needs will only be determined by activity or food/drink intake. It took me a total of almost 3 months to get my basals all set up, but now I could literally fast for 24 hours and my BGs wouldn't budge more than 20 points at any given time of the day.
That's it! That's how to do a proper basal test. I suppose you could set the day up into four 6 hour blocks, but IMHO this would just take longer to complete. Let me know if you have any questions or something didn't make sense-