Start by recording where your hours actually go for two weeks, because the answer is rarely what you assume. Most solo businesses find a substantial share consumed by administration, scheduling, invoicing, and the switching between them, rather than by the work customers pay for. Those are the tasks worth handing over, and they are usually invisible until they are counted.
The test for whether something can be delegated is whether you can write down how it is done. Take the task and describe it step by step. Somewhere in that list you will reach a point where the honest instruction is that it depends, and that point is the thing worth attention. It depends on what, exactly? Answering that converts a judgement you make unconsciously into a rule somebody else can apply, and it is the difference between a process that works without you and one that generates a phone call.
Delegate to a person or to a tool depending on what the task needs. Anything rule based and repetitive, such as appointment reminders, recurring invoices, or moving data between systems, should go to software rather than to a person. Anything requiring a decision about a specific customer should go to a person, or stay with you.
What should not be delegated first is anything customer facing where the relationship is the product, and anything you have never done yourself. Handing over work you do not understand means you cannot tell whether it is being done well, and you will discover the answer through a customer.
Expect the first handover to be worse than doing it yourself, and plan for that rather than treating it as evidence of failure. Taking a task back after one imperfect attempt teaches everybody that delegation is theatre, and it is the most common way this stalls.
Delegate the whole task rather than parts of it, including the decision about when it is done. Handing over the execution while keeping the judgement means the work still routes through you, and you have added a coordination step rather than removing a task. That halfway arrangement is the most common reason delegation feels like more effort than doing it yourself.
Then stop checking it after an agreed period. Reviewing every instance indefinitely recreates the original workload in a different form, and it signals to the person doing the work that they are not trusted with it. Agree what good looks like, check the first few, then move to checking periodically rather than continuously.