Hi Classy,
You are quite welcome! The rule of thumb I try to use is weight of the fabric with which you want to put the embroidery on. For instance a light weight cotton towel, I would use a no show mesh stabilizer along with Wss adhesive and a topping, sort of like an embroidery sandwich so to speak, with a vintage type design so as not to over load the fabric. Sometimes this can also help to make the fabric pucker by trying to put a design on it that the fabric just cannot handle no matter how much you stabilize it. The lighter the fabric, the more you need to stabilize it. A heavy towel for instance would require less stabilizer, generally I use a sheet of WSS adhesive on the bottom and a sheet of WSS on the top and that is sufficient.
Another thing to consider is what design are you using, typically a more dense design requires some alteration. As I said I usually just enlarge one that is so intense with stitches, by doing this you are changing the intensity of the design. Having the right design for the right fabric is the oldest dilema we face when trying to make that perfect gift. If I am embroidering on a light weight cotton flour sack towel I would use more and heavier stabilizers.
One thing to remember is to always do a test sew out using the same items you would use for the real one. By doing this you learn about the different fabric weights along with the different stabilizers. the key thing is to practice, practice practice! The more you do, the more you learn about the different aspects of all this. I never do any project with out first doing a test sew out. This tells you about your thread, top and bottom tension, design appearance, design desnsity, colors, stabilzers and placement.
Don't be so hard on yourself! No one learns all this over night. I have been doing this stuff for over 30 years, and every day is a new learning experience for everyone. You also need to know that there is no right or wrong method to use for this, what ever works best for you is usually the best method. Don't be afraid to TRY anything! Use different types of stabilzers and fabric combinations to achieve your desired results. Who knows you may come up with something no one has ever thought of before!
Read what you can about the different stabilizers, digitizers and methods. You will learn in time which embroidery sites, digitizers and designs work best for what you want. I know there are many New digitizers trying to break into the business also. Remember that they are new and learning their craft as well. Some sites are better than others, this all comes in time. Don't beat your self up over it!
There is one site in particular that the designs are spectacular, but very intense. Because they have so much detail, this also makes them very heavy, and you are embroidering over the same areas several times. This is why I enlarge them. The detail is still there but they are not so intense while sewing. Another, is a listing of new or resonably new digitizers, so some of the designs may not be all that wonderful when sewn out.
Also if you check on some websites they offer samplings of all their stabilizers that they carry, they will send you samples of them. This is a good way for you to see and feel the difference between them, and may help you to recognize then which are needed where. This is a great way to discover all that is out there for you to use also. One site in particular comes to mind, I will email it to you as I know it won't show up in here.
Just remember why you started this in the first place! Have fun with it! Don't get stressed over it, it will come in time, and most importantly get all the information you can about every product you use. Knowledge is power! Some products are better than others, buy small samplings of things like threads, stabilizers and the like. It will give you a chance to see how they work and if they are right for the item you want it for. Try everything! Don't get discouraged, we all have had designs fail, and sometimes you won't realize it until later, use that knowledge as a learning experience.
Remember too, that we all have gone through what you are going through right now, we have all felt that level of frustration. There are days I like to open the back door and toss it all out! Then there are days whe everything comes together so beautifully that you sit and wonder what did to make it do that!
Hang in there! We are all here to help you in any way we can!
Judy
Judy 
Help me to start each day with a new attitude and plenty of gratitude!