Although short looping lends itself well to the club environment, long looping can be used to become a second guitarist or backing track. I prefer this in relaxed environments where people are casually listening (or not) and eating their dinner.
The most seamless way I’ve found to do this is to record the loop while you are singing. Go through your verse and chorus until you reach the part where it will repeat and click your loop in. This way you don’t have to waste time and lose interest building a long loop without a melody. It can be difficult to do all of this and still have a metronomic loop. Solo performers almost always vary the tempo in different sections of songs, and you need unconscious control over your meter while you are singing. This only comes from practice with a metronome and all musicians really need this whether they are looping or not. Let me be the first to say I still need a lot of practice.
A problem with looping are the bridge sections of songs and key modulations. A lot of times you’ll have to rearrange songs to exclude these sections (as unfortunate as that is). But don’t fret- most people won’t even notice. For certain songs with important bridges I’ll just keep all harmonic elements separate from the percussion tracks and drop out the guitar/bass track while playing the bridge live over the drum track. This keeps a continuity in the flow of the song. Remember as long as you are staying on tempo you can go for long periods of time without any backing track and still retain the magic of the performance.
There will usually be a section of a song that lends itself best to looping- sometimes it’s best to just loop this section and bring it in while performing the rest of the song live. This allows you to not worry about major changes and still have the elements of a backing track at key moments. The way to achieve this is to keep your tempo while playing live the same as the tempo on the loop. There is a cheat to this if you are having trouble (which I often do). Make sure to watch the flashing tempo light on the pedal to make sure you are staying with the loop- this is a great way to keep yourself in check.
My style is based on pragmatism and function. I’m only looking to create basic accompaniments and make a full band sound. Other more famous loopers are creating incredible magic shows using huge setups and it’s up to you to decide who you are as a performer.