When printing at home, people generally have a workflow....
Make sure you get your monitor calibrated. Without proper calibration the rest of your workflow will not matter. This is also where a good quality monitor counts. Some people get the "spider" that measures and calibrates the monitor. I personally have heard great things about it but I have yet to try it. Adobe delivers an calibration wizard with Photoshop that should help out. My Mac came with its own utility to calibrate my cimena display.
Download the latest version of profiles for your specific printer. With the my epson 2200 and 825, the latest version made a world of difference. There is a specific profile for each type of paper. Getting the proper profiles for your specific printer is important.
Pictures should either have the embedded workspace or assigned one. I personally usually use the "Adobe RGB 1998".
Make the proper adjustments using the necessary "Adjustment layers".
Save the picture. At this point, this is the version I archive.
Crop the picture to the proper aspect. Use the cropping tool and set to the proper standard size ( 4x6, 5x7, 8x10 etc ). In general, I set the dpi between 300-400. This might be different depending on your printer and experience.
Apply the unsharpen mask filter. I do this on a case by case basis. Sometimes, its trial and error. I tend to be a bit more aggressive once I hit 8x10 or larger.
Send the print job to the printer. Read the recommended procedures for your specific printer. For Epsons, I select the proper target profile for the specific printer/media ( and in the case of the 2200 which type of black cartridge is loaded ) as well as other settings ( size/quality/etc.. ). These are all made within the photoshop dialogs. Once I hit "print", the epson driver takes over and pops up another set of dialogs. Here I set the printer ( again ), type of media ( again ), and at 1440 dpi. At that point, I let it go and wait for my print.
Again, this is specific to my setup and my experience ( mostly trial and error ). If the lab is making the print, ask them if there is a specific workspace they prefer and at what dpi. I do believe Adobe RGB 1998 is pretty common. If it is a competent photo lab, they'll have their own workflow for their specific printer. The best way is to simply ask and coordinate your efforts with their workflow.
Hope this helps....