My advice (I have worked in Florida as a planner, and am a certified plans examiner):
Access city records for the past year, and see what variances were requested, what the outcome was, and who represented them. Usually there is a firm or professional, and of-course, that could be plural, who have success getting things done in the jurisdiction. If you really-want to pursue the variance, spend the $ for a consultation with that person, or that firm. An ethical land use attorney or APA (American Planning Assoc.) member or AICP member (American Institute of Certified Planners) will have the experience, the knowledge of local ordinances and statutes, and will know the people with whom you will have to contend. They aren't going to be inexpensive, but if that's what you want, they are what I believe to be your best-chance for success.
At the planning & zoning meeting, do not volunteer anything unnecessarily. Actually, when you hire the land use firm/attorney and/or an APA/AICP professional, you probably should sit there, mute, and allow the professional to speak on your behalf. The people you're hiring do this for a living. They are not going to get excited like you might, when someone says something criticizing your hoped-for plan. Be quiet, sit there, let them earn their fee.
Sometimes the people making the decisions don't have a clue. However, your goal is to succeed in the variance application. Pointing-out how-stupid a planning & zoning board member is, or an elected official who is ignorant about your plan for your real property, doesn't share your dream of a lift-equipped shop, says-so, you cannot challenge them. Again, let the professional plead your case.
It's always helpful, and usually required to present a site plan with a sealed survey as the basis for your application, here in southeast Florida. It could also help your application chances if you provide them with some elevations (drawings) of the appearance of the building, and how it matches the architecture already existing on the parcel. Having a 100 year-old Craftsman style cottage w/cedar shake shingles, of modest dimensions, say, 1,500 sq. ft. 'under air,' as-is said, and wanting to build a CBS wall, standing seam seal metal roof for a building of 3,000 sq. ft. probably doesn't have much of a chance to be approved. Make the proposed building the same style, with similar details, give it some curb appeal to the view from the street: similar doors, windows, trim details, colors, and landscaping.
Only asking for one variance may also help you to achieve your desire. Don't look to encroach into a 20 ft side setback to within 5 ft. of the side property line or the rear p/l, while also exceeding the % of size of the parcel's primary use which is allowed, and having a building taller than-allowed, exceeding the permitted plot coverage for impermeable use, and sloping the runoff to the property lines, with no water retention plan. "That dog don't hunt!"
Providing a schedule of landscaping, using native species, and species which are drought-resistant, and xeriscape too, with at-least one elevation view of the building proposed with this flora will help to document your sincere desire to comply/conform with existing statutes/ordinances.
If your parcel is in an 'overlay district,' do whatever you can to fully-comply with the additional requirements found in the ordinances regarding this. Typical overlay districts would be for historic preservation, or certain commercial usages in that type of zoning.
If you read the zoning code, you can discover what the ordinances are to-which you will need to-comply. For instance, say the buffer for notice of a proposed variance is 1,000 ft. The GIS software that the city planners will use to generate the list of RPO's (registered property owners) to be notified is something that you may be able to do on your own, off the property owner's tax rolls. You could take the step of canvassing those people yourself and requesting them to sign a form letter for 'no-objection' for the proposed scope of development. Be aware that people raising objections to your plans don't need to-be from someone owning property within the 1,000 ft. buffer specified in the ordinance. Someone living miles-from your parcel could show-up at the hearing(s) and object to the scope of project. They may-be a city hall political gadfly who is a frequent speaker against any and all variance requests, because after-all, "rules are rules!."
Investigate what people who are going to be making the decisions have as pet-interests. Maybe one of the decision-makers is partial to butterfly gardens, or xeriscape. Look to incorporate those designs in your proposal.
Sometimes the consulting fee with a firm or attorney, planner, architect, or GC may prove to be the best money you can spend, because they can inform you that under the current leadership, you dream plan isn't likely to pass-muster. Sad, but many-times, true. Good luck.
