How can I get the seams to mach?

Which pattern are you using? Let us know and then perhaps I can give an informed answer. How many points etc. How did you cut it. As much information you can give will be helpful.

Are you using the fusible web pattern?

yes, more info please. and pics?

Several years ago I bought a precut quit package.That is what I am tring to sew now. The directions are very scimpy and don,t say anything about matching the seams after the curved pieces are sewn together in lon tapering rows. This is where I am stuck.I've tried several times,but can't seem to get the seams to go

Some thoughts that come to mind.
Does the picture show the seams matching?
Go back and check the seam allowance on all your inner seams. If they were not exact then the long seams won't match.
If you have one petal that is not sewn, lay it down matching the end points of each cross seam. Make sure the original cut was accurate. If you put a pencil dot where the hortzontal and verticle seam meet at the ends and then pin at these places you should be able to know if the original cut was accurate.
How many petals in your Dahlia.

Are you sewing by hand or machine. It is very important on the pattern that seams are consistent and accurate otherwise it won't match.

I made one. I hand peiced the whole thing but I think the best thing I learned is not to assume the cut peice is accurate. I cut a template the actual finished size of the finished peice and drew it onto the back of the fabric and used those lines as the sewing lines and didn't worry about the seam.

Yours is beautiful! I hope I can get mine to look like that. We are in the process of moveing just now to another smalltown in WI. Our youngesr son wants us nearer to him. After 78 yr of living in the same county this is proving to be rather traumatic for me.

Welcome to the Quiltingboard. I hope your move goes well and all is well. It will be different, just take one baby step at a time. Unpack all your favorite things, wrap yourself in a blanket, get online and talk to us. If you pull your drapes you can even pretend you are in your home town for a little while.
Maybe your Dahlia won't seem so hard after your moved, unpacked and all settled in.