Choose and tune the right 808
Start with a sample that fits the track. Some 808s have a clean fundamental, while others contain more distortion and upper harmonics. Pick one that works with the mood instead of trying to force every sample into the same role.
Tune the 808 to the song where practical, and check notes that sound unusually weak or boomy. Pitch changes can also alter how a sample behaves, so listen across the full bass line.
Make room for the kick
The kick and 808 can share low-frequency energy. Decide which element provides the initial punch and which carries the sustained bass. Their envelopes and timing should work together.
If the low end feels crowded, try adjusting the kick sample, shortening a sound or changing note placement before reaching for heavy processing. Sidechain compression can help in some mixes, but it is not the only solution.
Control level and dynamics
Avoid pushing the 808 so hard that it dominates every other element. Balance it against the drums and melody at a moderate listening volume, then check the mix quietly to judge whether the groove remains clear.
Use clipping or saturation deliberately if you want more audible harmonics. Excessive distortion can make the bass harsh, reduce headroom or cause problems on playback systems that cannot reproduce very low frequencies.
Check translation on different systems
Small speakers and phones may not reproduce the deepest bass. A controlled amount of upper harmonic content can help the 808 remain audible without relying entirely on sub frequencies.
Listen on headphones, ordinary speakers and a phone if available. Do not compensate for every playback system by making the bass excessively loud; aim for a balanced mix that translates reasonably well.
Keep the rest of the mix clean
Low-frequency instruments, long reverbs and layered samples can build up energy. Use high-pass filtering only where it makes sense, and avoid removing useful body from sounds simply to make the spectrum look tidy.
Compare your mix with a reference track at similar loudness. Focus on punch, clarity and groove rather than matching a waveform or loudness number.