Yes! Quilting is the one time where "fudge" can actually be Good for you!!

There are 3 main things that can make your blocks come out wrong. Cutting is the first one. Make sure that you are accurately measuring & your ruler isn't slipping. Use the same ruler for the entire project, but if you do need to use different rulers, try and use all the same brand. Then next is pressing. Make sure that you are not pressing a tiny pleat into the seam allowance when you press. Also, press, not iron. An up and down motion will keep the pieces from stretching. And finally we talk about the size of the seam, however, you don't measure the seam you measure the resultant patch. If you use a quarter inch foot, you may still have to adjust your needle position. Also, fabric and thread weight will affect your seam so it's a good idea to check at the beginning of every project. Here's how to check:
http://www.quiltingboard.com/tutoria...ce-t89997.html

You don't necessarily need to rip it up. I like your attitude of trying to learn from your mistakes, that is how I learned what I know today about quilting. Take a small ruler and find out where you went wrong. Are your blocks an 1/8" too small?? Check you seam allowance. Remember when you press a seam to one side you lose just a bit with the hump of the seams. Then I would check your cutting. I wish I could show you but a frend taught me where to put the line on the Omnigrid ruler.

I gave up quilting for over a year being disable with poor motor skills that I could not quilt any loner. What I use to compensate is to cut my strips 1/8" wider. It is amazing how many blocks you can press and starch at the end and then trim down. I learned this from Eleanor Burns. So I have been quilting for an additional 8 years. I try my best to avoid bias edges and triangles.

I agree with quiltsRfun "It takes a while to get the cutting and piecing accurate. If it really bothers you, take it out. In my case, I did the best I could and kept going forward. My first projects had many mismatched seams and cut off points. But I enjoyed what I was doing and didn't worry about it"

I've made about 5 or 6 myself, and none of them are perfectly matched up. I hope to get better with time and practice, but at the same time the eyesight is going so maybe they'll just start looking better to me lol

If you fabric isn't pressed before you cut it, it can grow or shrink when you press your blocks
If you are an 1/8 off once in a while, welcome to the world of quilting, fabric is forgiving.
If your blocks are all 1/8 off, if you are doing 16 blocks across, by the time you get to the end you are 2" off.

I had this trouble when I first started to quilt, I found out I needed to square up my blocks, which I did not do when I had the trouble.

This is EXACTLY why I hope to buy an accuquilt go...SOON!!

I was going to suggest the same tutorial... or one like it. It took me a long time to be consistent with my quarter inch seam. Some patterns can be fudged a bit without much notice if they are "off" but as you challenge yourself with intermediate patterns, you will want them to match up. Besides, I am a little OCD and needed to achieve an accurate quarter inch seam and now I am a much happier quilter.

Watch yourself when you come to the end of a seam. You my start off perfectly 1/4" but way go off just a tad at the end. Just be aware. Caught myself doing that!

One thing I have recently learned is when you cut your pieces, keep them stacked in the direction they were cut. The reason is, fabric has "give" (or stretches) selvage to selvage, but not lengthwise, so if you get them turned around, some blocks will stretch and others will not, so you get mismatched seams. My last checkerboard came out perfect using this info. None of the others have! With triangles, stack them in two piles, upper cuts, and lower cuts, and try to match the stretch directions for both piles with what you are joining them to. I stick a pin down through the "no stretch" edges so I do not mix them up.