Even though the pen drives speed is mainly depends upon hardware manufactures, by some simple tricks you will get enormous speed increment.
Here i will so you how to increase your pen drive read and write speed more than two times without any hardware modification and without using any software's.
I was done some Tests before and after the modifications and in all tests, i was taken a single file of 689MB (if you take small files like pictures or documents it’s take more time to write or read compared to a big one having same size, but here i was taken same file in all test. so which file was taken having no importance) , my pc (with OS: windows vista, RAM: 1GB, Processor: dual core 2.8GHZ) and a pen drive of size 4GB (kingston data traveler 2.0 usb device, Drive Name: PURUSHOTAM(I:)).Also tested by me on Transcend (2GB,4GB) and on Sandisk Pen Drives.
First of all i send (write) a file of 689MB mentioned above to my pen drive without any modification and the writing speed are shown below at two different time.In the beginning it is 2.62 MB/sec and at the end the speed is 5.69MB/sec. 
Now, I Format my pen drive with NTFS file system, which is don easily without using windows command (diskpart) or any external software's like Hp format tool .
For doing this go to My Computer>>Right click on your usb pen drive>>select properties from Menu>>and in that window go to Hardware tab>>in that tab select your your pen drive>>and click on properties button>>now a popup window open>>in that window select Policies tab>> in this tab choose optimize for performance>>then come back by clicking on ok button in both window. Now Format your pen drive as usual and select NTFS from drop-down menu in stead of FAT32 in Format window.If you don't understand or you have any confusion see in detail stepwise instructions with screen shoot. Format usb pen drive in NTFS without using any software’s or command prompt in windows. I separate detailed of Format because of the size of this article become large.If you know how to format in NTFS then you can format as you like and proceed.
Now after i completed the format, again i send the same file to the same pen drive and see the writing speed.I take two screen shoot at two different time shown below. In beginning it is about (20-30)MB/sec and at the end of writing it’s (12-14)MB/sec.
Notice that after your convert your pen drive file system from FAT32 to NTFS your data security and stability is also increases, you will get all the benefits of NTFS file system. You can also rename the usb pen drive in small letters in additions to only in capital letters in FAT32 drive.The only thing is that it take some space for file system don’t worry it take only 47MB for 4GB pen drive, which is negligible compared to it’s benefits.
Also i was tested my pen drive by USBDeview,if you don't know what is USBDeview then it is a small utility that lists all USB devices that are currently connected to your computer and test the Read and Write speed of the devices and much more. For more information about it or download go to this softpedia link. The screen shoot of the result is given below. 
It's gave almost constant results with some variations for a particular usb device and independent from file system and also it’s not 100% accurate.Don’t worry about this test you will get more than this result just follow the above instructions.Don’t worry about your pen drive if you don’t like you can revert back at any time by just format your pen drive in FAT32. Just try once.
The characteristic shown above may be different for different manufactures or models but in all cases you will get average read or write speed about two times to your previous read or write speed. If you got any problem just mention in comments.
