I keep this -
https://www.diabetes.org.uk/resources-s3/2017-11/carb-reference-list-0511.pdf - to give me an idea of carb content of various common things whilst I am learning. It helps to get a bit of a feel for what is what. Sweet potato is there but pumpkin and cornmeal are not but you can print it out and add them when you find out.
I also keep some kitchen scales handy so that I can weigh stuff - it is sometimes surprising just how small a portion is needed to get the carb content of something into what you might consider a low carb range. Oven chips are a good thing to experiment with. Decide on the carb level you are aiming for with a meal. See what your main items give you and then make it up to your target with ovenchips, using the carbohydrate in 100g of chips figure given on the packaging to work out the weight of chips needed. Weigh that amount out, and you will probably find that it is not worth turning the oven on to cook them! Don't suggest you get obsessive about it but if, like me, you are in the early days of sorting a low carb diet then it helps to get a perspective on things. It also helps when experimenting as suggested by trophywench.