I have a problem, I guess with seams?
 

When I sew 2 pieces together similar to logs of a log cabin, they lay smooth but right at the seam line, the piece I just attached TO, has little almost puckers, but not actually a pucker, just enough to make the piece look bad. Can you visualize what I'm describing? Can't get a picture from table to computer. I press to set the seams and press the sewn pieces. Doesn't help. Any suggestions? TIA

Hard to visualize your problem without a pic, maybe adjust your stitch length? Sorry I'm no help, hope somebody can help.

try sewing with the join on top, the edges may be catching in your feed dogs

Have you tried lowering your tension?

Does your machine have adjustable foot pressure? I've experienced something that sounds like what you're describing, and it turned out the presser foot was pushing down too hard and causing the seams to look "puckery" (for lack of a better term).

I think Joe'smom, sewnoma, Annie68 have offered good advice. Try stitching a long seam on some scrap fabric. and experiment.

I would start with different settings for the pressure on the presser foot. Is this a sewing machine you have used for a long time, or is it new to you?

One of my vintage machines will do that if the tension is off - just had it happen this week. The other possibility has been mentioned above- too much pressure from the presser foot. Another is feed dogs too high.

I'm curious: if you sew two pieces the exact same length together, does the top one seem to end up a little longer after they are sewn? And the puckers can't be pressed out?
That would indicate, to me, that the feed dogs are "gathering up" too much of the bottom piece of fabric. If you can adjust the feed dog height, or the presser foot pressure, one of those might help.

Do you have a piece of fabric to start the beginning of the sewing? That way you have a "leader" fabric to to through the the needle first and then start your logs to sew together and then start the next one leaving two or three stitches and go on to the next block sewing together.

In addition to the previous recommendations, I suggest that you always work with a leader and ender piece. I just have small scrap pieces laying by the machine that I use to start a seam and end a seam.