I had to do one without a solver as there was multiple solutions and it wouldn't give me any of them.
I would say, however, that by using the website of the solver to help you solve it and then copying the results over helped so so much. It greens workable results and reds bad ones.
Also, 5 in all boxes where there is a 1 on the side.
2 along from the 2 can only be 4 or 5, and after that it's a bit hit and miss.