Article in English: Your Mac OS X and other software updates can keep your system stable and running smoothly. Updates should install automatically, but it's good to check every once in a while and see if an essential update is queued. Open the Mac App Store and click the Updates tab at the top of the window. Review and install any available updates for your system and installed programs. If you're running low on free space, your Mac's performance may take a hit. Clearing out old files and programs can go a long way towards improving your Mac's responsiveness.  Uninstall old programs by dragging them from the Applications folder to the Trash. Check your Downloads and Documents folders to see if there are any old files that you can delete. Programs like CleanMyMac3, Disk Inventory X, and DaisyDisk can find and remove tons of old junk files from your computer. You can free up a significant amount of space using a file removal tool. Use Monolingual to remove unused language files. You can get it for free from monolingual.sourceforge.net/. Don't remove the language you use or the English language, as this can cause problems with the operating system. If your desktop is chock full of icons, this could be slowing down your system. Pare down your icons and files on your desktop to help improve performance. Some programs will set themselves to start as your Mac boots up. This makes it slightly easier to load the program when you need it, but too many will make your Mac take forever to start.  Click the Apple menu and select "System Preferences." Select the "Users & Groups" option then select "Login Items." Select an app that you want to prevent from loading at startup and click the "-" button. You may need to click the padlock and enter your admin password first. Sometimes files and permissions get corrupted, which can cause problems with your Mac. The included Disk Utility can scan for and fix these types of problems.  Launch Disk Utility from the Utilities folder in the Applications folder. Select your hard drive in the left frame....

Summary in Vietnamese:
Cài đặt các bản cập nhật mới nhất. Giải phóng dung lượng lưu trữ trên ổ cứng. Gỡ bỏ các biểu tượng thừa thãi khỏi desktop. Tắt bớt những chương trình khởi động cùng hệ điều hành (startup). Kiểm tra ổ cứng bằng Disk Utility.