Speaking as someone who has worked at various Renaissance Faires for years, please don't do an 'off the shoulder' shirt - it's completely wrong for the period.
The rest of the project should be pretty easy, except for the Bodice. There *are* some 'historical' patterns available which are a very good starting place. For the skirt, you can either make a series of rectangles gathered into a waistband, or you can cut triangles (with the point lopped off) for a skirt that is fuller at them & not so bunchy at the waist. The shirt should be a high coller (like a mandarin) tied at the neck with rectangles of fabric gathered into it and regular set-in sleeves with cuffs that tie like the collar. I don't make my shirts fasten up the front because I like to open them to expose cleavege. The bodice will be the most difficult part of this project, as it should be fitted tightly and laced up the front. The first time I made a bodice, I adapted a pattern, made the bodice, and then had to take it in 3 times before it fit right. You'll need boning up the front to keep it stiff and provide support. There's a great book called Elizabethan Costuming by Janet Winter & Carolyn Shultz that can help a beginner adapt modern patterns to Elizabethan Silhouttes.
Good luck & enjoy your faire...