Free: Contests & Raffles.
If your rifle is older, check the CUP pressure tolerance posted by maker and cross check that with load data in your manual so that you are not exceeding it. Most manuals take that into account when they publish a max load. Do a lot of reading first and start with starting loads and you should be fine, but get the other tools mentioned, like calipers and case trimmer. Inspect your brass, go slow and be careful.
If your rifle is new, you should be fine by sticking to book data. Start near the lower end of the range for a given powder type and bullet weight and work up, watching for pressure signs as you go. Your rifle will eventually tell you what a max load is in that rifle. Keep in mind that there are many things that affect this. If you find your rifle's max load now and then shoot the same ammo in july, you may see dangerously high pressures. Higher temperatures increase pressure. This is just one reason that knocking on the door of max loads is not necessarily ideal.
Most of the newer books are pretty conservative on what they show for max charges, so you should be safe going all the way to max. Of course you always want to watch for pressure signs as wildman stated but in most cases you should be able to get to the max book powder charge if you're using identical components (primers, cases, bullet). It's pretty hard to get yourself in serious trouble if you're loading a cartridge like the 25-06 and if you're using one of the slowest powders, which are also the ones that will provide maximum velocities. As an example, with my 270 Win (very similar to your 25-06) I use H4831 and generally about 58 grains with 150 grain bullets. This charge fills up the case and I don't think I could get more than maybe 60 grains in the case and still be able to seat the bullet. If I did mistakenly get 60 grains in there I am sure it wouldn't be enough to cause any real problems. So there's really no need to worry about "blowing up your gun" or anything like that. Now if you were loading pistol cartridges and using the fast powders that generally work in them, you could easily get a double charge, which probably would blow up the gun. But for just loading your 25-06, don't sweat it too much.