Hi! So I have done Spanish since S3, so I had a decent basis of having done Nat5 (I think I got something like 93% in the exam) This being said, Spanish was one of the few subjects I felt a jump in from Nat5 to Higher, mainly in the writing aspect. I'm not sure if you have said previously about doing Nat5? But either way, I can hopefully give some advice/tips on how I coped (as believe me, I didn't think I would at Higher ahah)
-I found reading not too bad. This was because it's only the one text vs the 3 at Nat5, and whilst the difficulty is more intense I found it pretty much the same as it was a continuous text it provided more context that helped me find and at some points guess the answers. As at Higher you do a translation as part of reading too, this does make this paper a bit more difficult. This is because it has to be pretty much exact, the marking scheme only allows slight variations. However, it does help as the marks are split up into 5 sections within- so if you get the first section of the translation wrong, but the others more accurate, you can still gain 8/10 if that makes sense?
-Listening... honestly just keeping up with reading vocab and practising past papers is my best advice as I normally only got like 60-70% on average for each listening as, if I'm honest, I would have to end up playing a guessing game based off of the answers I did get and any other context I picked up
-I hate to say it but grammar... I actively avoided grammar at Nat5 (lol) and managed to do decent, however- at Higher I really had to try focus on this and especially the imperfect/preterite tense when it came to writing. It's easier said than done, but once you start picking it up on how to form verbs in the past tenses, it helps you in all aspects a tonne!
-For writing, I kinda struggled as I would try to challenge myself to write what I wanted to write instead of what I knew how to write, which isn't always a great idea. My best tip is to have a basic structre for each context your school chooses to teach (IE- Society, Learning, Friends and Family etc) as usually, you can get away with the same sentence structures and just change the contents to fit the question. This helps your writing flow better which can boost your mark up, even if accuracy sometimes lacks. But also try to vary your language to try to make it less monotonous, as this also increases your chance of landing a higher mark.
-For speaking, I always did the best in this aspect. But honestly, all I would do is use the speaking booklet the school provides with the questions you will be asked and write sophisticated answers that were a good length but not too confusing to memorise, and then I would get them marked and fixed until they were 100% accurate and then write the final answers on flashcards and memorised them from there. At Higher, you can be asked some introductory questions that aren't planned or some that slightly vary to the ones in the book- however, as long as you have memorised answered to the planned questions, you can normally wing them and alter them to fit a slightly different angle of question.
Honestly, I loved Higher Spanish and can't wait to continue with AH (pending results day and if I meet my A target ahah) I would say just try and be consistent and it will come to you a lot easier and quicker. I hope the above tips help, but if you have any specific questions let me know and I'll try my best to help!