Tomatoes are the easiest to can, pickles too, they do not need a hot bath, only hot jars, boiling temp and they will seal themselves.
One rule of thumb, if in doubt, throw it out. Also, always listen to your jars, they will talk to you!!!! When you are done canning, we have always counted the pops for sealing, if you only have 4 pops out of 6 jars, check them over, 2 did not seal and you want to use those quickly (in a few days). Wipe your jar tops to make sure they are clean before placing the lid on. Also, listen to the seal when you open it. If it has a good sssssssssssssp! then it was a good seal, or a POP, another good seal. A tinny sounding click with a short ssp, not good enough.
Weird I am...lol. Good luck with canning, you will never go back to store bought! Foods are so real tasting and less in sodium and you know what they were rinsed in and grown in.