Having a method of organising your songs is a good idea. For example, you might want to categorise your songs into different folders, or identify genres of songs using the necessary #tag. This makes finding songs easier, and morever, in the case of folders, can keep your pool of songs limited to those that match the tastes of your fellow gameplayers for Party Mode.
Playlists are arguably an easier way of doing this; mainly because one song can appear on multiple lists. They are also very easy to put together. There are a couple of methods you can use...
The first method involves USDX's built-in function. Simply load the software and go to the 'Sing' option. Find the song you want (press 'J' to open the search function), and press 'M' to open the menu:
Select "Add Song":
Select "To New Playlist":
Type in a name for your playlist, and select "Create." Then, find the next song you want to add, press "M" again, then "Add Song," then add it to your new playlist by making sure that its name is displayed and selecting "to existing playlist."
Easy enough! However, wouldn't it be nice to drag and drop from a list, rather than having to pick songs out individually? UltraStar Manager can help you there!
Load this program and direct it to your main songs folder. If the Playlist window is not showing on the right hand side, click "view" and then select "Playlists." Then, click on "Create" at the bottom of the window.
Type in a name for your playlist, and click on the "Save as" button at the bottom. Give it an appropriate filename, and save. Make sure that it is saved in your standard playlists directory (C:\Program Files\UltraStar Deluxe\playlists, by default)
Now all you need to do is right-click on any song listed in your collection, and click "send to playlist," and continue adding songs until you're happy with it. You will need to click "save" before you exit, and the playlist should appear in UltraStar when it is next loaded.
It is possible to create song lists from playlists using UltraStar Manager - you might want to do this for when choosing a setlist for Party Mode proves to be difficult. However, if the lists are appropriately named (i.e. by decade or genre), then that's the most information that people need anyway.