Make sure the material is studio-ready. You should work on song arrangements before the studio session starts. This is known as pre-production, and it gives you the chance to tweak all aspects of the material so you spend studio time engineering audio rather than rehearsing material. You should tighten up arrangements, fine-tune tempos and edit lyrics beforehand--songs should be polished before you record. The most advanced engineering skills in the world won't rescue a poorly written song.
Check your audio equipment. People often don't maintain their equipment. Check hardware effects processors, amplifiers, microphones and cables regularly, and repair or replace any malfunctioning parts. Equipment that fails or works intermittently can ruin an otherwise productive recording session.
Use the "gain" control on your recording software to monitor the recording levels of all inputted instruments and microphones before recording tracks. Although it's good to have a hot signal when recording, having the levels peak at 0dB or above will cause the distortion known as "clipping" of the signal. Back in the days of analog-tape recording, overloading a signal resulted in a tape saturation that could add warmth and a pleasing distortion to a track. In digital recording, when you clip a signal, it cuts of parts of the digital information, and the result is a harsh and unpleasant sound.
Experiment with microphone placement on all instruments to get the best possible sound from them. There are many different microphone types and endless ways to position them, so take the time to try different approaches and make notes of successful combinations for future reference. A microphone that sounds perfect when close to a loud electric guitar speaker may not work so well when you try to capture the nuances of an acoustic guitar, so don't expect one microphone in one position to adequately capture every instrument.
Click the "Record" button on your recording software program to arm your tracks to record, and plug in a pair of headphones so you can monitor the performances as you record them. Click on the "Play" button to begin recording and the "Stop" button to finish recording. Repeat this process, adding different instruments and vocals to the mix until you finish your recording.
Make a stereo mix of all of your recorded tracks. Bring up the channel volume faders controlling the drums and bass guitar, and see if you can get them to gel. If you can get the rhythm section to sound cohesive, it will serve as a solid foundation for the rest of the song. Bring in the guitars, raising their volume levels until they fit snugly with the rhythm tracks. Continue to add other instruments until you have a blend that pleases you, and then finish by bringing the vocals into the fold.
Adjust the equalization controls in your recording software program to fine-tune the tonal character of your tracks. An equalizer allows you to boost or cut different frequencies to alter the sound and give tracks a little separation so they can be heard clearly. If too many instruments and voices are in a similar frequency range, they can fight with each other to be heard, and if you increase their volume, you overload the mix, causing ear fatigue for the listener.
Adjust the panning of your tracks to create sonic space for them. Often, tracks sitting in the same area of the stereo field may clash and lack definition, but sometimes all you need is a turn of the pan control to give them separation. For example, you can clean up muddiness resulting from a piano track and an organ track both being panned hard left in the mix by panning one of them hard right, so that each part occupies its own space in the stereo field. Experiment with the pan control of all tracks until you find their sweet spot. That will clean up your mixes without raising volume levels.