Video tutorials are a sculptor's best friend. Here are some useful ones, though no doubt they will send you on a YouTube tangent. Think about every process in terms of sculpture. Think about processes you already know how to do (baking, sewing, collage, home improvement, origami, photography, robotics, gardening, DIY craft projects) can be used in sculpture.
PAPER MACHE TO CREATE REALISTIC FORMS: https://www.youtube.com/watch?v=2vlFkRngRQY Notice how many layers are involved and how she is improvising with common materials for the right effect. It all starts simple and rough, like drawing the figure. Start wth basic forms and measurements and then slowly refine through layers.
EPIC FOAM SCULPTING: https://www.youtube.com/watch?v=XBChVsORoPE Notice how they use reference images and measurements. They use many layers in this construction and they plan out the order of these layers ahead of time. Since it's a big piece, they have already considered how they will transport it by building it in pieces and re-connecting it with spray foam gap filler on site (then going over the layers again in those cracks, no doubt).
MEDITATIVE CLAY SCULPTING: https://www.youtube.com/watch?v=zqtkZcjIz4M I found this when I was making a claymation last year. Sometimes it gets addicting to watch technical videos, but you'll find once you've watched a bunch, you just gave yourself a mini education in no time. Also this mouth is wicked cool.
PLASTER WASTE MOLD: https://www.youtube.com/watch?v=SwI5-CSGO2I Very thorough informative tutorial in plaster waste mold. This would be one of the cheapest ways to make molds because it involves re-usable clay and a bag of plaster. When you watch casting videos, it is immediately apparent that there are an infinite number of methods. Start out with something cheap to get a handle on the basic idea of mold-making- a positive, a negative built around the positive that can release from the positive, a new positive object.
SILICONE 2-PART MOLD: https://www.youtube.com/watch?v=FQ1A7ZjTsx8 Smooth-on makes the sexy stuff. I don't recommend using it for your first mold because it's expensive. A 2-part mold is for a pretty basic object and silicone can be cast into many many times, so this is a true production mold. While you don't need to start off with expensive industry-specific materials, watch the Smooth-on videos to know how to do things with precision. They use gloves, non-stick coated plastic mixing containers, one-time use mixing sticks and even something called a 'mold-strap'. But don't be fooled- you don't really need this. The more you know your stuff the less you buy into these expensive products.
INFLATABLES: https://www.youtube.com/watch?v=5KPvuOkWCDI Entertaining video.