For locating targets when polar alignment may be a bit off, I suggest star hopping. Start with a bright star that cannot be mistaken for anything else, then move towards the target star, if necessary locating and centering some other stars of intermediate brightness along the way.
The guide image in spectroscopes tends to be of lower quality due to the transfer optics, but it is a lot better than it used to be. I find that I can sometimes solve my guide images with Astrometry.net, but not always. I’ve also taken to storing a guide image, so that I can always go back and check if the spectrum turns out to be unexpected. Observing variable stars can be a bit easier as there will often be a BAA chart and/or and AAVSO chart. With these I find it straightforward to confirm that I’ve got the right star.
That is a great first spectrum. I agree something does not look right with the continuum, but it can take some trial and error to get the response profile working well. Robin’s suggestion of observing 2 Miles stars, and using one to create the response profile to correct the continuum on the other is very good. Especially if you choose A or B type stars which have simple spectra so it is easier to see what is going on with the response profile. The correspondence between the features in the spectra shows that your wavelength calibration is working well.