I used to really struggle with this, so let me offer some advice.
learn as many transitions as you can. practice getting from mount “a” to mount “b” in as many ways as you possibly can. watch good yoyoers and learn there transitions, even if they’re unappealing to you. doing this has really helped me. also when making tricks, it’s usually best to not try to make one big combo at once; instead, make a ton of short tricks, and then you can combine those tricks in the order that is most aesthetically pleasing. if you study Yuuki’s yoyoing you’ll notice that his combos are like 10 different short tricks. if you compare his older freestyles to his newer ones, you’ll notice some of the tricks in his combos are the same, even though the combos are different.
also just mess around a lot. get lost in some good music and just try random stuff as you’re practicing. some of that stuff will stick and you’ll start getting new tricks, and those tricks will eventually become combos.
don’t stick to learning one type of tricks. i.e. just because you do tech don’t think you shouldn’t try to learn any ‘jensen-y type yoyoing’ and visca versa. learning as many styles of 1a will definitely help you develop a more well rounded and better looking style.
a great way to get more combos is to take your current combos, cut them in half, and then simply add an intro and an outtro to both sections and wah-lah you now have twice the combos. this is a great thing to do if you need more material for a freestyle.
also, don’t spend your practice sessions doing the same tricks you already know over and over again…new tricks aren’t magically going to form like that. but instead, just try out a LOT random stuff, and like i said some of that stuff will stick.
if all else fails, get inspiration elseware. take a break from yoyoing and go spin some poi or something. every skilltoy I’ve ever gotten into has taught me things that i’ve been able to apply to my yoyoing. my flow has gotten a lot better lately and i believe that’s been due to spinning poi. or else, maybe just taking a break from 1a for a little while and doing a different style will give you more ideas.
breaking down and learning other players combos is also a great way to improve your own yoyoing. yes, it’s boring and tedious as heck, but, I think it is well worth it. when i first was really getting into tech and was having a hard time improving, I learned yuuki spencer’s combo (or part of it) known as ‘soiled panties’ and I came up with a new combo of my own in no time.
hope this helps