Handicap sailing a Cherub can be frustrating, but it can also be very rewarding. Just keep plugging away at it, and then ONE DAY, you will have the right wind and the right course and you will do very well indeed! The rest of the time, it is a case of 'what could have been'.
We have a 97 Rules Bistro which over time we managed to tune to the point where it would actually point rather well, perhaps at the sacrifice of speed. This was essential for racing against other non cherubs as otherwise you would spend the whole day sailing in everyones dirty air... which is not fast. We have our rig raked less than some, and also, really work upwind to make as much height as possible, making decisions with every gust whether to head up to gain height, or foot off to make the most of the speed depending on who or what was around us at the time.
Another place where you can win or lose a lot, is at the top mark. Depending on what other boats are around you makes a big difference as to whether you keep high at the mark to get the kite up, or soak down low, to then head up and build the apparent wind. As you have probably already realised, hooking into a decent gust with the kite up really shoves a rocket up the arse of the little boat. So look around and try and pick the best option to avoid the amount of time NOT flat out planing. We would quite often soak down as low as possible to give ourselves a bit of space from the boats above us, and then by the time we were hooked into a gust you could normally go through and out from underneath the other plodders downwind. (if windy this is risky though, as you might find that you then struggle to point up high enough to make the mark without ragging the kite!)
As with all sailing, the single most important place to get it right is the start. If you can get out and clear on the first beat, and keep as many of the high pointing plodders behind you, then it will give you many more options. Get around the top mark and get the power down and you should then be clear of the others for a while. Get it wrong and you spend the first beat mucking about going the long way around lasers and RS things, then you are compromised on the downwind... and then you are down the pan.
If you can master sailing the boat in a handicap race, then you will be surprised by how well you can do against other Cherubs. Bottom line, keep the boat moving at all times... but don't lose sight of the fact that you need to keep it moving in the right direction too!