Hi and welcome to Lorwolf! I recommend equipping your wolves with companions and playing with the companions as often as you can (you can play with most of them every hour but some have 2hr+ cooldowns) to generate pebbles. As a newer player I remember it taking a while to generate a decent amount of pebbles. Some more advice off the top of my head are as follows:
1. Save your MS for den expansions, cooking space etc and MS exclusive items and avoid buying food, seeds, supplies for MS if you can. There are a lot of items listed in the Flea Market for 1-2MS, but unless it's a pretty wolf or something you *really* need, I recommend against it so you can get other upgrades. Currently, 1 Moonstone is ~100,000 pebbles and 1 Moonstone shard is around 10,000 pebbles.
2. Complete scenarios in the campaign and win battles in the gauntlet. The campaign and gauntlet will both drop items you can use or sell.
3. Sell any White Candlesticks you get from your inventory. They each sell for 35pebbles a piece. Currently the only other use for them is to make the pumpkin apparel. You can get candles in a variety of ways.
4. Keep your bones and bone paste! You will need these to craft many many items. (Sell them if you want, but if you just start out i'd recommend working up towards at least 300 bones and 100 bone paste before selling)
5. Farming corn, pumpkin, and fogweed is a good way to get food. Each of those crops takes 20 minutes to grow and each food item will give you 5 energy. Fishing is also a great way to generate food. You can cook the fish and the cooked fish will give 20 energy vs 5 energy for raw fish.
6. Browse the forums, there are many useful guides that can point you in whichever direction you want to go!
7. Don't be afraid to reach out for help, but watch out for inactive threads. Many members have hosted giveaway's with some being current and some being inactive. If you see a giveaway, always check to make sure that it is still being maintained or else you might be waiting a while ;)
8. Save any "Leaf Pile" drops you get. These are used to craft some apparel items and it can be quite grindy to collect them.
9. Have fun and play at your own pace. Whether you like to spend big or have a more relaxed playstyle, there's ultimately no "wrong" way to play ^-^