Remember to take a BUMP and not a LINE. Meth is not coke. I've seen coke users try meth for the first time, and cut up these huge lines of crystal. Then they'd do a line or two, not feel that much (because meth takes a bit to kick in fully), and so do more. 15 minutes later it would all hit them like a ton of bricks, and in a very unpleasant manner (as described above). So, realize that you probably only will need a little (if it's good stuff) and that you should wait 10-15 minutes before doing more, just to make sure that you actually need another bump.
Personally, I love meth as I'm sure everyone knows. If it's good, and you take the right amount, it can be a very euphoric buzz with a good body high. Not as euphoric as MDMA but a similar type of body high and feeling.
Realize that there are many ways of doing meth. It can be eaten (the way that you would eat MDMA), smoked, snorted, or injected. I have tried all 4 ways so I will give you an idea of how these methods of administration vary:
Snorted: Pros -- hits you pretty quickly. You get a slight rush. You don't need a whole lot. Many people also enjoy the ritual of cutting it up and snorting it. It still lasts quite a while when you do it like this (~5 hours) but not as long as when you take it orally. Cons -- it burns like a bitch. It is corrosive (damaging) to your nose, mouth, and throat. The drip can be yucky -- though many learn to love the taste (and even the burn). The high is more jittery when you snort, I have also found.
Smoked: Similar to snorting it, but with more of a rush. Again there is a ritual here that many like, and smoking/passing the pipe can be a fun social activity. Smoking meth also results in the shortest meth high, which can be good or bad depending on your purposes. As when snorted, you don't need a lot of meth to get fucked up. The cons -- smoking meth is even worse for you than snorting it (bad for you lungs as well as throat/mouth etc). I also find the high to be even more jittery than the snorted high.
Injected: Pros -- healthier for you than snorting or smoking. Very clean feeling, nice rush. Intense body high. Lasts about 4 hours (which can be good or bad, again). You don't need that much to get high (though for a real nice high you do need a few bumps worth). IVing meth is, IMO, much more euphoric and less jittery than the two previous ways of doing meth. The ritual of setting up the IV injection if wonderful, if you have a needle fetish like I do. Cons -- IV drug use tends to be more addictive, plus you need to be careful and follow the usual guidelines of IV drug use. If you accidently IV too much, you could increase your chances of a meth-related heart attack/heart failure.
Orally: This is my personal favorite. Pros -- lasts a long time (6-8 hours). Very euphoric, nice rushy comeup. Good body high. Feels very 'clean' -- ZERO jitteriness (unless you OD). This is also the healthiest manner to do the drug, and it is harder to OD from oral meth. Cons -- lasts a long time (if you don't want to be up all night). Many say the 'rush' isn't the same -- though the body high from oral meth is better (and I prefer a drawn out amazing body high to a short lived mediocre rush...but that's just me). Also, this method doesn't have the 'ritual' aspect that the others methods do.
Anyways, there is tons more info if you search, but hopefully you'll be able to decide from my synopses which ways of administration are most appealing to you...