One of the best ways to last-hit and avoid missing autoattacks and skills, is without holding the mouse. Its better attack individually instead of continously. Its kinda annoying when you start playing like it. But then you get used to it.

During teamfights dont hesitate attacking like crazy or you gonna miss alot of skills and ultis like scylla ulti and Ao kuang ulti (if you use it too early before waiting the mark) wait few seconds, read your opponent moves and then use it. Something that use to happen is that your team yell at you telling you to do something that you know is completly wrong and even when you know that its wrong you end doing it and failing, and have to wait all the CDs to use it. Few times ive had my teammates insulting me for not using Neith Ulti when someone has low hp but there are situations when its not convenient and i prefer canceling it and not using it for multiple reasons, If you hesitate and shoot it inmediately you could lock the wrong target and waste it, i know how much damage Neith ulti does and im sure it wont kill it or their whole team is covering him and it would be a bad dea risking it.

Maybe the best way to practice is conquest co-op. But for PvP i prefer Assault since its only one lane, you dont have to worry about jungle ganks, and Assault matches are short. But yeh... the down side is that its random pick and you might be unlucky, but if you have bad luck. Look the positive side, atleast you can practice a new role. And remember, noone is pro since the beginning, we all start as "news or noobs" and end being good. Btw Freya is a good choice to start since she can be melee and ranged at the same time and her 3 is good to practice your prediction skills. Sol is amazing but the only problem with Sol is that you must try to keep her psssive up and for it you have to keep using your skills all the time and trying to hit all your basic attacks. You will get good with the god you most like. Im an old player so idk which are the best gods to learn each role atm. But Imo as tank i would recommend Ymir or Sobek., ADC Neith, Artemis or Apollo. Jungle Mercury, loki or baka. For Support i learned with Aphro. Mid the god the god you most like. But its not mandatory, you can learn with any god

(Sorry for my mistakes, im on cellphone and my mothers language isnt english, tried my best). Btw if you want i could help you in game. Just message me your smite name to add you or i could send you mine.

Hope you enjoy Smite and Have fun.