If you are offering a unique product, you might be able to raise your prices. If you are in an underserved market, you might be able to raise your prices. If you are offering the same services as everyone else, you will need to be aware of market prices and figure out other ways to increase profits.
I would be wary of using other people's commercial property, and even driving client's vehicles, without the proper insurance. You will need garage keepers insurance, and seperate endorsements to use properties other than those covered by your current general liability policy. Ditto for hiring subcontractors, they will need their own general liability coverage, and you will need certificates of insurance in good standing. In addition, review the laws concerning how the government determines who is a contractor and who is an employee (insurance companies know, and will go where they smell money – you need to be protected and all jobs fully doocumented to prove contractor status). The costs and liabilities of working this way are high and you may find it is not worth the hassle or the risk.
I would also be concerned if you are working more than 40 hours per week. Studies too numerous to count have proven that anything over 40 hours/week makes people less productive. An occasional 50 hour week may be acceptable, but anything over that will likely have a negative effect on your business (to say nothing of your family life and mental health). If you (or your employees) are working more than fifty hours a week you are on a collision course with disaster.
If you offer unique fabrication skills or have recognized and marketable design skills (and the portfolio, awards, and industry record to prove it), you might be able to name your price and grow your business slowly and sustainably. You will be making money based on the value of your unique skills. If you are a commercial printer, then volume, scale, and good business management skills will be what drives your profits (the competition is tough in this space – the entry level cost of opening a digital print shop is relatively low). Check wholesale pricing for the products you sell, and if you can't beat those prices, you are facing an uphill battle. Look around; you can see small shops getting gobbled up by bigger, well funded companies, and those bigger companies being bought up by investment firms who can provide the funding to build large scale printing and fabrication facilities with economies of scale (maximizing the ROI on equipment, the ability to offer good paying jobs and retain employees with benefits and sustainable working conditions, better raw materials pricing, and huge advantages on shipping and logistics).
One of the best ways for a small shop to make money is to offer comprehensive installation, service, and maintenance services. Rather than investing in fabrication and printing (products that can be bought wholesale and shipped to your door with little or no liability), you might consider buying reliable service vehicles and equipment and building a staff of quaified service technicians. Local service companies will attract national accounts and local businesses who can buy or supply signs and printing, but absolutely depend on local service companies for installation, service, and maintenance. Finding and retaining field service employees is easier these days than finding $20/hr - $25/hr general shop employees. You will be paying them closer to $35/hr base rate and can afford to offer them comprehensive benefits in addition to their salaries. Once you have established a reliable, profitable service company, you can slowly venture into fabrication and expanding in-house printing capability and grow a healthy full-service company.