When choosing sounds, there are a few things you can look at.
- Frequency range. Instruments are designed to play in a certain frequency range. For example, a piano has a very broad frequency range, going from low bass frequencies to high high frequencies. A tuba only plays in the low- to low-midsection, and a piccolo only plays in the high section. Combining sounds that each play in a section usually works well in the song. For example, you can have one sound playing a melody in the midsection, and another sound playing a melody on top of that in the high section. You can also do this with your synths and samples.
- Length of sounds. Different sounds have different lengths. You can play very long, slow notes, or short, plucky notes, or anything in between. Usually, it works well when you combine different types of sounds together. For example the lower sound plays slower, long notes, and the higher sound plays faster, plucky notes. If you combine multiple sounds with the same lengths, it may sound cluttered.