All the above advice is good -- I'll summarize it in a concise list of instructions.
Start with 100% juice. Most commercial juices are poor wine making material, as they contain preservatives including potassium sorbate and potassium metabisulfite. Sorbate is what we (home wine makers) use to stabilize a dry wine before backsweetening -- it prevents a renewed fermentation. If there is sorbate in your juice, getting a fermentation going is difficult. Not impossible, but if I see sorbate on the ingredient list, I'd put it back on the shelf.
Check your specific gravity (SG). The initial SG should be between 1.070 and 1.100, with 1.090 being a good starting point. If the SG is higher, the yeast may be in too rich an environment and won't start. If the SG is lower, the environment is poor.
If you don't have a hydrometer, get one. Without it you will be unable to determine the initial sugar level, and will not be certain when fermentation is complete. Fermentation stopping does not mean it's complete. It just means it stopped for some reason.
Optional -- Add a yeast nutrient to help ensure the environment is best for yeast growth.
Take the yeast out of refrigeration 6-12 hours before use, e.g., put it on the counter before you go to bed. It needs to be at room temperature when you rehydrate it.
Rehydrate the yeast before use, following the instructions in the document listed above.
Room temperature is critical! The yeast is already trying to grow is what is probably not an ideal environment, so the temperature must be at least 70 F. Given the situation, I'd rather have closer to 80 F.
Good luck!