It's hard to count 1234 while leading?
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That's why you have to internalize the beat - know where you are without consciously counting. See also here. – Richard Metzler Sep 10 '18 at 7:19
It's what you don't do! As long as you're aware of where beat 1 is, that's all you need. Tapping a foot, nodding a head, shrugging a shoulder.
If you have a metronome with a 'ding' available on beat one, set it.
Chords usually change on each bar, and often every four bars a new line will occur, so you should be aware of that. Presumably you're playing with a band, so get the drummer to do something special at the beginning of each line, which is probably where you'll end one phrase and start another. A splash cymbal for example.