Often I have heard that people will put bed risers under their cutting tables to make them the right height.
When you start a long cut, put pressure on the lower half of the ruler. Then stop cutting, walk your fingers to the next section and keep cutting. If you try to control the ruler for a single cut, it is easy to shift the ruler.
I make sure that my fabric hangs properly when held salvage to salvage before I fold it to cut. That avoids the "Vs".
When I have to make multiple cuts, I add the widths and make one cut to that width before sub-cutting that piece.
Example, instead of cutting 4 strips of 2.5" in a row, I cut one strip of 10" and then sub-cut that into 5" and 2.5"
If I keep making separate cuts, I check periodically that my fabric is still square. You'll be amazed how much shift you can accumulate.
As far as the height - go to Walmart or Bed Bath and Beyond and get the stack of bed risers - that is what our guild uses when we have a work day or go on retreat. it will be stable easy to store if you dont want the table high all the time.
If you want perfect strips, I really recommend the June Tailor Shape Cut ruler. It is the best ruler I have ever bought.
The best money I have ever spent on my quilting notions. And I have a lot of quilting rulers. It might really help you. And if you sign up for Joann's e-mails, they will have printable coupons that you can use.
I have also found that I need to stand EXACTLY in front of my ruler/fabric when cutting. If I stand off to the side then I tend to cut crooked. Also I have seen PVC pipe cut and used to heighten table just cut them all the height that yiu neet to raise your table to a good height for you.
be aware the lines on some cutting mat's are NOT RIGHT. My olfa bought at jo anns caused me no end of frustration before one of the sales ladies i was asking why I couldn't get this bear claw to come out right told me to get an acrylic ruler with a grid on it and check it.
I use the Quilters Slide Lock for all my rulers. It keeps the ruler from moving and you will never have to worry about cutting your fingers. Always use some type of safety cutting tool when you cut with a rotary cutter. The cutter can jump in a blink of an eye. If you have a heavey broken iron don' t throw it out. It will work to hold a long ruler in place when cutting strips, I taped some sandpaper on the bottom of the iron and it will not slip on the ruler It will work until you can buy a nicer tool. Rotary cutting your finger is scary and it hurts!
All the tips in this thread are great, and a couple are new to me. Here's another one to keep rulers from moving. I use those large clamps found in tool stores...some are spring loaded and some you tighten by squeezing the handles until they lock into position. Those have a release lever on the inside. I avoid the spring ones because of arthritis...too stiff and hard to use for me. The others are wonderful for holding down rulers and even square rulers. One clamp on a lower corner is enough and you can use your hand to hold down the upper corner (on the same side of the ruler). The clamp works great with the 4 by 36 inch ruler. One clamp on the bottom and the other clamp at the top....work well for me.