Generally speaking it is easier to o/c by upping the front side bus (FSB) frequency. Doing this offers 2 benefits.
1) You dont have to worry about having to unlock your cpu in order to change the multiplier.
2) AMD durons and athlon love higher fsb settings more than upping the cpu multiplier.
You could try upping the fsb by 5mhz at a time and if the system starts acting funny then you need to bring it back down.
Also... and this is a BIGGY!!! Know How To Clear Your CMOS Before You Start!!! There is usually a jumper on the motherboard to clear your cmos and restore your bios settings to factory default. Messing with bios settings can cause your system not to boot at all!
If you have some good memory then overclocking through the FSB is excellent. If your memory doesnt like being overclocked along with your cpu then you can look into unlocking your cpu and upping your cpu multiplier.