Do start with a condition survey. Before choosing finishes, find out what the structure, roof and drainage are actually doing. Original character is only worth restoring if the building behind it is sound.
Do repair original material where possible. Old-growth cypress, heart pine and plaster outperform most modern replacements. Milling a new piece to match an existing profile almost always beats swapping in a stock part.
Don't seal an old house up like a new one. These homes were designed to breathe. Insulation and air sealing need to be planned so moisture can still escape rather than collecting inside wall cavities.
Don't skip the review process. Many neighborhoods here have guidelines covering windows, siding, paint and visible changes. Confirming requirements early prevents expensive rework later.
Do budget a contingency. Opening walls in a century-old house reveals surprises. A realistic reserve keeps a discovery from stalling the whole project.