Regarding the thread to use, you are going to get TONS of opinions on that one. I, personally, use Maxi-Lock serger thread in gray. This is a polyester thread and I've not had any problems with quilts falling apart, becoming torn with the thread or anything. Some folks will say 100% cotton only personally I say, what works best for you and your machine.
Regarding what color, for piecing I use a neutral gray or natural color. No stead fast rules on color to use.
On machine needles the lower the number the smaller the needle. For piecing I use a 10 or 11 quilting, embroidery, or microtex needle. These all have sharp points and IMHO give the best results. If I am using a heavier fabric in piecing I will bump up to a 12 or 14 quilting or embroidery needle.
You will find needles marked UNIVERSAL. These needles can be used in stretch, knit fabrics or woven fabrics. I only use Universal for knits.
Hope this info helps.