OK I'm pretty sure we all know that you start off with 15 mil from the starter (It may have changes by now) but thats not always enough. There is a simple way to make money fast, while also upgrading these skills.
Thieving
and
Woodcutting
So thieving starts off as 100k (or around there) on the first stall and the very slow progression of stats should earn you around, well, 1 Mil a minute. The stalls in money go (remember this may not be accurate) 100k, 150k, 250k, 350k, 450k. One you get to the 450 K you can get about one steal every five seconds, in other words 450 * 12 = 5400 or 5.4 Mil a minute
Woodcutting is by far the easiest skill to get up and i get about 30k a second at 120 WC, cutting REGULAR TREES. The harder it is to cut the less productive it is for both money and leveling. Keep hacking. 30*3600 (3600 seconds) = 10800 or 10.8 Mil a Minute, exactly 2x thieving
Ok I know what your saying how can I make money doing combat skills?
WELL, there are a few
Slayer Tower (fight abyss demons)(easiest, they have 1 hit on you then they are done)
Pking (Medium) ONLY IF YOU ARE COMBAT 126 PLUS there is no lvl system in wild any1 anywhere can attack you.
And finally Jad and the Kal Queen (Extreamly Hard) would recommend not doing unless you have like 120 att str def and health lol, trust me their hard, I am still a noobish person at like lvl 101 and I cannot put a scratch on them
My final hint is Simple
Pay attention to the text box for drop parties and contests. I have given away bils of items and i know 1337 has too.
Please add me in game and PM me if you need anything
0wnage