You could trying squeezing with your legs and if they don't respond to that, kick with your heels a little bit. If there is still no response use a crop just to tap, your horse will soon learn that if he/she responds to your squeeze then the kick and tap can be avoided. Make sure you're clear with what you want and don't mix up your signals. Hope this helped xx
Put your leg on if theres no response put it on harder if theres again no response tap with a dressage whip behind your leg on their flank or bum. You have to be really consistent to get the message through. But this is pretty much the only way to remind them. I wouldn't use spurs if your legs unsteady as this will just make them ignore spurs too!
Use a crop to get them to react a bit more, no hitting just a gentle tap to apply at bit of aid. Hitting means they could gain behavioural problems but just tapping means they will react a bit more to your leg